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Xu R, Crassee I, Bechtel HA, Zhou Y, Bercher A, Korosec L, Rischau CW, Teyssier J, Crust KJ, Lee Y, Gilbert Corder SN, Li J, Dionne JA, Hwang HY, Kuzmenko AB, Liu Y. Highly confined epsilon-near-zero and surface phonon polaritons in SrTiO 3 membranes. Nat Commun 2024; 15:4743. [PMID: 38834672 DOI: 10.1038/s41467-024-47917-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 04/12/2024] [Indexed: 06/06/2024] Open
Abstract
Recent theoretical studies have suggested that transition metal perovskite oxide membranes can enable surface phonon polaritons in the infrared range with low loss and much stronger subwavelength confinement than bulk crystals. Such modes, however, have not been experimentally observed so far. Here, using a combination of far-field Fourier-transform infrared (FTIR) spectroscopy and near-field synchrotron infrared nanospectroscopy (SINS) imaging, we study the phonon polaritons in a 100 nm thick freestanding crystalline membrane of SrTiO3 transferred on metallic and dielectric substrates. We observe a symmetric-antisymmetric mode splitting giving rise to epsilon-near-zero and Berreman modes as well as highly confined (by a factor of 10) propagating phonon polaritons, both of which result from the deep-subwavelength thickness of the membranes. Theoretical modeling based on the analytical finite-dipole model and numerical finite-difference methods fully corroborate the experimental results. Our work reveals the potential of oxide membranes as a promising platform for infrared photonics and polaritonics.
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Affiliation(s)
- Ruijuan Xu
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27606, USA
| | - Iris Crassee
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland
| | - Hans A Bechtel
- Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yixi Zhou
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland
- Beijing Key Laboratory of Nano-Photonics and Nano-Structure (NPNS), Department of Physics, Capital Normal University, Beijing, China
| | - Adrien Bercher
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland
| | - Lukas Korosec
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland
| | - Carl Willem Rischau
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland
| | - Jérémie Teyssier
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland
| | - Kevin J Crust
- Department of Physics, Stanford University, Stanford, CA, 94305, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - Yonghun Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | | | - Jiarui Li
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - Jennifer A Dionne
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Harold Y Hwang
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
- Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - Alexey B Kuzmenko
- Department of Quantum Matter Physics, University of Geneva, 1211, Geneva, Switzerland.
| | - Yin Liu
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27606, USA.
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2
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Cao Y, Sun H, Chen Y, Ma L, Li L, Jin S, Wu W. A self-aligned assembling terahertz metasurface microfluidic sensor for liquid detection. NANOSCALE 2024. [PMID: 38639046 DOI: 10.1039/d4nr00466c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
This paper reports a new terahertz metasurface microfluidic sensor, which is actually a kind of reflective terahertz metasurface absorber with a microfluidic-channel structure located in the strong field energy region of the absorber. The metasurface structure is made on an ultra-thin quartz substrate as the cap layer, while a two-step structure is made on a silicon substrate as the pedestal layer. In order to precisely control the thickness of the microfluidic channel, the cap layer is self-aligned assembled with the pedestal layer to form the terahertz metasurface microfluidic sensor. The obtained sensor could enhance the light-matter interaction, resulting in high sensing performance. The measured results show that the sensor has a perfect absorption peak at 2.60 THz and a high Q-factor of 62.59, which are basically consistent with the simulated results. The sensitivity and FOM calculated based on the measured results of different liquids with different refractive indices is 0.733 THz per RIU and 16.4, respectively. Compared with some recently related work, the sensitivity is increased by about 40%, the Q-factor is increased by 3-5 times, and the FOM is increased by 5 times, which make the sensor have great application potential for solution detection in the terahertz frequency band.
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Affiliation(s)
- Yunhao Cao
- National Key Laboratory of Advanced Micro and Nano Manufacture Technology, School of Integrated Circuits, Peking University, Beijing 100871, P. R. China.
| | - Hongshun Sun
- National Key Laboratory of Advanced Micro and Nano Manufacture Technology, School of Integrated Circuits, Peking University, Beijing 100871, P. R. China.
| | - Yusa Chen
- National Key Laboratory of Advanced Micro and Nano Manufacture Technology, School of Integrated Circuits, Peking University, Beijing 100871, P. R. China.
| | - Lijun Ma
- National Key Laboratory of Advanced Micro and Nano Manufacture Technology, School of Integrated Circuits, Peking University, Beijing 100871, P. R. China.
| | - Liye Li
- National Key Laboratory of Advanced Micro and Nano Manufacture Technology, School of Integrated Circuits, Peking University, Beijing 100871, P. R. China.
| | - Shengxiao Jin
- National Key Laboratory of Science and Technology on Space Microwave, CAST Xi'an, P. R. China
| | - Wengang Wu
- National Key Laboratory of Advanced Micro and Nano Manufacture Technology, School of Integrated Circuits, Peking University, Beijing 100871, P. R. China.
- Beijing Advanced Innovation Center for Integrated Circuits, P. R. China
- Frontiers Science Center for Nano-optoelectronics, Peking University, P. R. China
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3
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Zheng H, Zheng Y, Ouyang M, Fan H, Dai Q, Liu H, Wu L. Electromagnetically induced transparency enabled by quasi-bound states in the continuum modulated by epsilon-near-zero materials. OPTICS EXPRESS 2024; 32:7318-7331. [PMID: 38439415 DOI: 10.1364/oe.517111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 02/01/2024] [Indexed: 03/06/2024]
Abstract
Highly tunable electromagnetically induced transparency (EIT) with high-quality-factor (Q-factor) excited by combining with the quasi-bound states in the continuum (quasi-BIC) resonances is crucial for many applications. This paper describes all-dielectric metasurface composed of silicon cuboid etched with two rectangular holes into a unit cell and periodically arranged on a SiO2 substrate. By breaking the C2 rotational symmetry of the unit cell, a high-Q factor EIT and double quasi-BIC resonant modes are excited at 1224.3, 1251.9 and 1299.6 nm with quality factors of 7604, 10064 and 15503, respectively. We show that the EIT resonance is caused by destructive interference between magnetic dipole resonances and quasi-BIC dominated by electric quadrupole. Toroidal dipole (TD) and electric quadrupole (EQ) dominate the other two quasi-BICs. The EIT window can be successfully modulated with transmission intensity from 90% to 5% and modulation depths ranging from -17 to 24 dB at 1200-1250 nm by integrating the metasurface with an epsilon-near-zero (ENZ) material indium tin oxide (ITO) film. Our findings pave the way for the development of applications such as optical switches and modulators with many potential applications in nonlinear optics, filters, and multichannel biosensors.
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4
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Serebryannikov AE, Ozbay E. Exploring localized ENZ resonances and their role in superscattering, wideband invisibility, and tunable scattering. Sci Rep 2024; 14:1580. [PMID: 38238347 PMCID: PMC10796346 DOI: 10.1038/s41598-024-51503-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 01/05/2024] [Indexed: 01/22/2024] Open
Abstract
While the role and manifestations of the localized surface plasmon resonances (LSPRs) in anomalous scattering, like superscattering and invisibility, are quite well explored, the existence, appearance, and possible contribution of localized epsilon-near-zero (ENZ) resonances still invoke careful exploration. In this paper, that is done along with a comparison of the resonances of two types in the case of thin-wall cylinders made of lossy and loss-compensated dispersive materials. It is shown that the localized ENZ resonances exist and appear very close to the zero-permittivity regime, i.e., at near-zero but yet negative permittivity that is similar to the ENZ modes in thin planar films. Near- and far-field characteristics of the superscattering modes are investigated. The results indicate that the scattering regimes arising due to LSPRs and localized ENZ resonances are distinguishable in terms of the basic field features inside and around the scatterer and differ in their contribution to the resulting scattering mechanism, e.g., in terms of the occupied frequency and permittivity ranges as well as the sensitivity to the wall thickness variations. When the losses are either weak or tend to zero due to the doping with gain enabling impurities, the sharp peaks of the scattering cross-section that are yielded by the resonances can be said to be embedded into the otherwise wide invisibility range. In the case of lossy material, a wide and continuous invisibility range is shown to appear not only due to a small total volume of the scatterer in the nonresonant regime, but also because high-Q superscattering modes are suppressed by the losses. For numerical demonstration, indium antimonide, a natural lossy material, and a hypothetical, properly doped material with the same real part of the permittivity but lower or zero losses are considered. In the latter case, variations of permittivity with a control parameter can be adjusted in such a way that transitions from one superscattering mode to another can be achieved. In turn, transition from the strong-scattering to the invisibility regime is possible even for the original lossy material. The basic properties of the studied superscattering modes may be replicable in artificial structures comprising natural low-loss materials.
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Affiliation(s)
- Andriy E Serebryannikov
- Division of Physics of Nanostructures, ISQI, Faculty of Physics, Adam Mickiewicz University, 61-614, Poznan, Poland.
| | - Ekmel Ozbay
- Nanotechnology Research Center (NANOTAM), Bilkent University, 06800, Ankara, Turkey
- National Institute of Materials Sciences and Nanotechnology (UNAM), Department of Physics, and Department of Electrical Engineering, Bilkent University, 06800, Ankara, Turkey
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5
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Ling YC, Yoo SJB. Review: tunable nanophotonic metastructures. NANOPHOTONICS 2023; 12:3851-3870. [PMID: 38013926 PMCID: PMC10566255 DOI: 10.1515/nanoph-2023-0034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 08/08/2023] [Indexed: 11/29/2023]
Abstract
Tunable nanophotonic metastructures offer new capabilities in computing, networking, and imaging by providing reconfigurability in computer interconnect topologies, new optical information processing capabilities, optical network switching, and image processing. Depending on the materials and the nanostructures employed in the nanophotonic metastructure devices, various tuning mechanisms can be employed. They include thermo-optical, electro-optical (e.g. Pockels and Kerr effects), magneto-optical, ionic-optical, piezo-optical, mechano-optical (deformation in MEMS or NEMS), and phase-change mechanisms. Such mechanisms can alter the real and/or imaginary parts of the optical susceptibility tensors, leading to tuning of the optical characteristics. In particular, tunable nanophotonic metastructures with relatively large tuning strengths (e.g. large changes in the refractive index) can lead to particularly useful device applications. This paper reviews various tunable nanophotonic metastructures' tuning mechanisms, tuning characteristics, tuning speeds, and non-volatility. Among the reviewed tunable nanophotonic metastructures, some of the phase-change-mechanisms offer relatively large index change magnitude while offering non-volatility. In particular, Ge-Sb-Se-Te (GSST) and vanadium dioxide (VO2) materials are popular for this reason. Mechanically tunable nanophotonic metastructures offer relatively small changes in the optical losses while offering large index changes. Electro-optically tunable nanophotonic metastructures offer relatively fast tuning speeds while achieving relatively small index changes. Thermo-optically tunable nanophotonic metastructures offer nearly zero changes in optical losses while realizing modest changes in optical index at the expense of relatively large power consumption. Magneto-optically tunable nanophotonic metastructures offer non-reciprocal optical index changes that can be induced by changing the magnetic field strengths or directions. Tunable nanophotonic metastructures can find a very wide range of applications including imaging, computing, communications, and sensing. Practical commercial deployments of these technologies will require scalable, repeatable, and high-yield manufacturing. Most of these technology demonstrations required specialized nanofabrication tools such as e-beam lithography on relatively small fractional areas of semiconductor wafers, however, with advanced CMOS fabrication and heterogeneous integration techniques deployed for photonics, scalable and practical wafer-scale fabrication of tunable nanophotonic metastructures should be on the horizon, driven by strong interests from multiple application areas.
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Affiliation(s)
- Yi-Chun Ling
- Department of Electrical and Computer Engineering, University of California, Davis, CA95616, USA
| | - Sung Joo Ben Yoo
- Department of Electrical and Computer Engineering, University of California, Davis, CA95616, USA
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6
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Saha S, Diroll BT, Ozlu MG, Chowdhury SN, Peana S, Kudyshev Z, Schaller RD, Jacob Z, Shalaev VM, Kildishev AV, Boltasseva A. Engineering the temporal dynamics of all-optical switching with fast and slow materials. Nat Commun 2023; 14:5877. [PMID: 37735167 PMCID: PMC10514334 DOI: 10.1038/s41467-023-41377-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 09/01/2023] [Indexed: 09/23/2023] Open
Abstract
All-optical switches control the amplitude, phase, and polarization of light using optical control pulses. They can operate at ultrafast timescales - essential for technology-driven applications like optical computing, and fundamental studies like time-reflection. Conventional all-optical switches have a fixed switching time, but this work demonstrates that the response-time can be controlled by selectively controlling the light-matter-interaction in so-called fast and slow materials. The bi-material switch has a nanosecond response when the probe interacts strongly with titanium nitride near its epsilon-near-zero (ENZ) wavelength. The response-time speeds up over two orders of magnitude with increasing probe-wavelength, as light's interaction with the faster Aluminum-doped zinc oxide (AZO) increases, eventually reaching the picosecond-scale near AZO's ENZ-regime. This scheme provides several additional degrees of freedom for switching time control, such as probe-polarization and incident angle, and the pump-wavelength. This approach could lead to new functionalities within key applications in multiband transmission, optical computing, and nonlinear optics.
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Affiliation(s)
- Soham Saha
- School of Electrical and Computer Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Argonne National Laboratory, Lemont, IL, 60439, USA
| | | | - Mustafa Goksu Ozlu
- School of Electrical and Computer Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - Sarah N Chowdhury
- School of Electrical and Computer Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - Samuel Peana
- School of Electrical and Computer Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - Zhaxylyk Kudyshev
- School of Electrical and Computer Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | | | - Zubin Jacob
- School of Electrical and Computer Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, USA
| | - Vladimir M Shalaev
- School of Electrical and Computer Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, USA
| | - Alexander V Kildishev
- School of Electrical and Computer Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, USA
| | - Alexandra Boltasseva
- School of Electrical and Computer Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA.
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN, USA.
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7
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Moitra P, Xu X, Maruthiyodan Veetil R, Liang X, Mass TWW, Kuznetsov AI, Paniagua-Domínguez R. Electrically Tunable Reflective Metasurfaces with Continuous and Full-Phase Modulation for High-Efficiency Wavefront Control at Visible Frequencies. ACS NANO 2023; 17:16952-16959. [PMID: 37585264 DOI: 10.1021/acsnano.3c04071] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
All-dielectric optical metasurfaces can locally control the amplitude and phase of light at the nanoscale, enabling arbitrary wavefront shaping. However, lack of postfabrication tunability has limited the true potential of metasurfaces for many applications. Here, we utilize a thin liquid crystal (LC) layer as a tunable medium surrounding the metasurface to achieve a phase-only spatial light modulator (SLM) with high reflection in the visible frequency, exhibiting active and continuous resonance tuning with associated 2π phase control and uncoupled amplitude. Dynamic wavefront shaping is demonstrated by programming 96 individually addressable electrodes with a small pixel pitch of ∼1 μm. The small pixel size is facilitated by the reduced LC thickness, strongly suppressing cross-talk among pixels. This device is used to demonstrate dynamic beam steering with a wide field-of-view and high absolute diffraction efficiencies. We believe that our demonstration may help realize next-generation, high-resolution SLMs, with wide applications in dynamic holography, tunable optics, and light detection and ranging (LiDAR), to mention a few.
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Affiliation(s)
- Parikshit Moitra
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Xuewu Xu
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Rasna Maruthiyodan Veetil
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Xinan Liang
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Tobias W W Mass
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Arseniy I Kuznetsov
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
| | - Ramón Paniagua-Domínguez
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore
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8
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Dixit KP, Gregory DA. Nanoscale modeling of dynamically tunable planar optical absorbers utilizing InAs and InSb in metal-oxide-semiconductor-metal configurations. DISCOVER NANO 2023; 18:100. [PMID: 37566175 PMCID: PMC10421843 DOI: 10.1186/s11671-023-03879-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/31/2023] [Indexed: 08/12/2023]
Abstract
The attainment of dynamic tunability in spectrally selective optical absorption has been a longstanding objective in modern optics. Typically, Fabry-Perot resonators comprising metal and semiconductor thin films have been employed for spectrally selective light absorption. In such resonators, the resonance wavelength can be altered via structural modifications. The research has progressed further with the advent of specialized patterning of thin films and the utilization of metasurfaces. Nonetheless, achieving dynamic tuning of the absorption wavelength without altering the geometry of the thin film or without resorting to lithographic fabrication still poses a challenge. In this study, the incorporation of a metal-oxide-semiconductor (MOS) architecture into the Fabry-Perot nanocavity is shown to yield dynamic spectral tuning in a perfect narrowband light absorber within the visible range. Such spectral tuning is achieved using n-type-doped indium antimonide and n-type-doped indium arsenide as semiconductors in a MOS-type structure. These semiconductors offer significant tuning of their optical properties via electrically induced carrier accumulation. The planar structure of the absorber models presented facilitates simple thin-film fabrication. With judicious material selection and appropriate bias voltage, a spectral shift of 47 nm can be achieved within the visible range, thus producing a discernible color change.
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Affiliation(s)
- Kirtan P. Dixit
- Department of Physics and Astronomy, The University of Alabama in Huntsville, 301 Sparkman Drive, Huntsville, AL 35899 USA
| | - Don A. Gregory
- Department of Physics and Astronomy, The University of Alabama in Huntsville, 301 Sparkman Drive, Huntsville, AL 35899 USA
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9
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Moitra P, Wang Y, Liang X, Lu L, Poh A, Mass TWW, Simpson RE, Kuznetsov AI, Paniagua-Dominguez R. Programmable Wavefront Control in the Visible Spectrum Using Low-Loss Chalcogenide Phase-Change Metasurfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2205367. [PMID: 36341483 DOI: 10.1002/adma.202205367] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 11/01/2022] [Indexed: 06/16/2023]
Abstract
All-dielectric metasurfaces provide unique solutions for advanced wavefront manipulation of light with complete control of amplitude and phase at sub-wavelength scales. One limitation, however, for most of these devices is the lack of any post-fabrication tunability of their response. To break this limit, a promising approach is employing phase-change materials (PCMs), which provide fast, low energy, and non-volatile means to endow metasurfaces with a switching mechanism. In this regard, great advancements have been done in the mid-infrared and near-infrared spectrum using different chalcogenides. In the visible spectral range, however, very few devices have demonstrated full phase manipulation, high efficiencies, and reversible optical modulation. In this work, a programmable all-dielectric Huygens' metasurface made of antimony sulfide (Sb2 S3 ) PCM is experimentally demonstrated, a low loss and high-index material in the visible spectral range with a large contrast (≈0.5) between its amorphous and crystalline states. ≈2π phase modulation is shown with high associated transmittance and it is used to create programmable beam-steering devices. These novel chalcogenide PCM metasurfaces have the potential to emerge as a platform for next-generation spatial light modulators and to impact application areas such as programmable and adaptive flat optics, light detection and ranging (LiDAR), and many more.
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Affiliation(s)
- Parikshit Moitra
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore, 138634, Singapore
| | - Yunzheng Wang
- Singapore University of Technology and Design, Singapore, 487372, Singapore
- Optics Research and Engineering, Shandong University, Qingdao, 266237, P. R. China
| | - Xinan Liang
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore, 138634, Singapore
| | - Li Lu
- Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Alyssa Poh
- Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Tobias W W Mass
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore, 138634, Singapore
| | - Robert E Simpson
- Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Arseniy I Kuznetsov
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore, 138634, Singapore
| | - Ramon Paniagua-Dominguez
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore, 138634, Singapore
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10
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Shrewsbury BK, Audhkhasi R, Povinelli ML. Symmetry breaking of dark-mode metamaterials for voltage-switchable infrared absorption. OPTICS LETTERS 2023; 48:2441-2444. [PMID: 37126293 DOI: 10.1364/ol.484163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We propose electrically reconfigurable absorbers with switchable narrowband resonances in the infrared. Our absorbers consist of two coupled, identical resonators and support a dark supermode. We show that by dynamically breaking the symmetry of the system, the dark supermode can be made to couple to an incoming plane wave, producing a narrowband absorption peak in the spectrum. We use this effect to design and optimize absorbers consisting of coupled metal-insulator-metal resonators based on gallium arsenide. We show that the switching functionality of the designed device is robust to fabrication imperfections, and that it additionally serves as a spectrally tunable absorber. Our results suggest exciting possibilities for designing next-generation reconfigurable absorbers that could benefit several applications, such as energy harvesting and sensing.
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11
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Ma W, Zhou C, Chen D, You S, Wang X, Wang L, Jin L, Huang L, Wang D, Miroshnichenko AE. Active quasi-BIC metasurfaces assisted by epsilon-near-zero materials. OPTICS EXPRESS 2023; 31:13125-13139. [PMID: 37157457 DOI: 10.1364/oe.486827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Active devices play a critical role in modern electromagnetic and photonics systems. To date, the epsilon (ε)-near-zero (ENZ) is usually integrated with the low Q-factor resonant metasurface to achieve active devices, and enhance the light-matter interaction significantly at the nanoscale. However, the low Q-factor resonance may limit the optical modulation. Less work has been focused on the optical modulation in the low-loss and high Q-factor metasurfaces. Recently, the emerging optical bound states in the continuum (BICs) provides an effective way for achieving high Q-factor resonators. In this work, we numerically demonstrate a tunable quasi-BICs (QBICs) by integrating a silicon metasurface with ENZ ITO thin film. Such a metasurface is composed of five square holes in a unit cell, and hosts multiple BICs by engineering the position of centre hole. We also reveal the nature of these QBICs by performing multipole decomposition and calculating near field distribution. Thanks to the large tunability of ITO's permittivity by external bias and high-Q factor enabled by QBICs, we demonstrate an active control on the resonant peak position and intensity of transmission spectrum by integrating ENZ ITO thin films with QBICs supported by silicon metasurfaces. We find that all QBICs show excellent performance on modulating the optical response of such a hybrid structure. The modulation depth can be up to 14.8 dB. We also investigate how the carrier density of ITO film influence the near-field trapping and far-field scattering, which in turn influence the performance of optical modulation based on this structure. Our results may find promising applications in developing active high-performance optical devices.
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12
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Zubritskaya I, Cichelero R, Faniayeu I, Martella D, Nocentini S, Rudquist P, Wiersma DS, Brongersma ML. Dynamically Tunable Optical Cavities with Embedded Nematic Liquid Crystalline Networks. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209152. [PMID: 36683324 DOI: 10.1002/adma.202209152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/21/2022] [Indexed: 06/17/2023]
Abstract
Tunable metal-insulator-metal (MIM) Fabry-Pérot (FP) cavities that can dynamically control light enable novel sensing, imaging and display applications. However, the realization of dynamic cavities incorporating stimuli-responsive materials poses a significant engineering challenge. Current approaches rely on refractive index modulation and suffer from low dynamic tunability, high losses, and limited spectral ranges, and require liquid and hazardous materials for operation. To overcome these challenges, a new tuning mechanism employing reversible mechanical adaptations of a polymer network is proposed, and dynamic tuning of optical resonances is demonstrated. Solid-state temperature-responsive optical coatings are developed by preparing a monodomain nematic liquid crystalline network (LCN) and are incorporated between metallic mirrors to form active optical microcavities. LCN microcavities offer large, reversible and highly linear spectral tuning of FP resonances reaching wavelength-shifts up to 40 nm via thermomechanical actuation while featuring outstanding repeatability and precision over more than 100 heating-cooling cycles. This degree of tunability allows for reversible switching between the reflective and the absorbing states of the device over the entire visible and near-infrared spectral regions, reaching large changes in reflectance with modulation efficiency ΔR = 79%.
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Affiliation(s)
- Irina Zubritskaya
- Geballe Laboratory for Advanced Materials, Stanford University, 476 Lomita Mall, Stanford, CA, 94305, USA
- Department of Physics, University of Gothenburg, Origovägen 6B, Gothenburg, 41296, Sweden
| | - Rafael Cichelero
- Department of Physics, University of Gothenburg, Origovägen 6B, Gothenburg, 41296, Sweden
| | - Ihar Faniayeu
- Department of Physics, University of Gothenburg, Origovägen 6B, Gothenburg, 41296, Sweden
| | - Daniele Martella
- European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, Sesto Fiorentino, 50019, Italy
- Istituto Nazionale di Ricerca Metrologica (INRiM), Strada delle Cacce 91, Torino, 10135, Italy
| | - Sara Nocentini
- European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, Sesto Fiorentino, 50019, Italy
- Istituto Nazionale di Ricerca Metrologica (INRiM), Strada delle Cacce 91, Torino, 10135, Italy
| | - Per Rudquist
- Department of Microtechnology and Nanoscience - MC2, Chalmers University of Technology, Kemivägen 9, Gothenburg, 41296, Sweden
| | - Diederik Sybolt Wiersma
- European Laboratory for Non-Linear Spectroscopy (LENS), University of Florence, via Nello Carrara 1, Sesto Fiorentino, 50019, Italy
- Istituto Nazionale di Ricerca Metrologica (INRiM), Strada delle Cacce 91, Torino, 10135, Italy
- Physics and Astronomy Department, University of Florence, via G. Sansone 1, Sesto Fiorentino, 50019, Italy
| | - Mark L Brongersma
- Geballe Laboratory for Advanced Materials, Stanford University, 476 Lomita Mall, Stanford, CA, 94305, USA
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13
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Saha S, Segal O, Fruhling C, Lustig E, Segev M, Boltasseva A, Shalaev VM. Photonic time crystals: a materials perspective [Invited]. OPTICS EXPRESS 2023; 31:8267-8273. [PMID: 36859942 DOI: 10.1364/oe.479257] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
Recent advances in ultrafast, large-modulation photonic materials have opened the door to many new areas of research. One specific example is the exciting prospect of photonic time crystals. In this perspective, we outline the most recent material advances that are promising candidates for photonic time crystals. We discuss their merit in terms of modulation speed and depth. We also investigate the challenges yet to be faced and provide our estimation on possible roads to success.
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14
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Zhang Y, Li L, Xie H, Jiang Z, Li Y, Wang T, Yao D, Liu Y, Han G, Hao Y. Compact non-volatile ferroelectric electrostatic doping optical memory based on the epsilon-near-zero effect. APPLIED OPTICS 2023; 62:950-955. [PMID: 36821150 DOI: 10.1364/ao.477763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 12/28/2022] [Indexed: 06/18/2023]
Abstract
With the booming development of optoelectronic hybrid integrated circuits, the footprint and power consumption of photonic devices have become the most constraining factors for development. To solve these problems, this paper proposes a compact, extremely low-energy and non-volatile optical readout memory based on ferroelectric electrostatic doping and the epsilon-near-zero (ENZ) effect. The writing/erasing state of an optical circuit is controlled by electrical pulses and can remain non-volatile. The device works on the principle that residual polarization charges of ferroelectric film, which is compatible with CMOS processes, are utilized to electrostatically dope indium tin oxide to achieve the ENZ state. Simulation results show that a significant modulation depth of 10.4 dB can be achieved for a device length of 60 µm with an energy consumption below 1 pJ.
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15
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Li W, Xu M, Xu HX, Wang X, Huang W. Metamaterial Absorbers: From Tunable Surface to Structural Transformation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2202509. [PMID: 35604541 DOI: 10.1002/adma.202202509] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/28/2022] [Indexed: 06/15/2023]
Abstract
Since the first demonstration, remarkable progress has been made in the theoretical analysis, structural design, numerical simulation, and potential applications of metamaterial absorbers (MAs). With the continuous advancement of novel materials and creative designs, the absorption of MAs is significantly improved over a wide frequency spectrum from microwaves to the optical regime. Further, the integration of active elements into the MA design allows the dynamical manipulation of electromagnetic waves, opening a new platform to push breakthroughs in metadevices. In the last several years, numerous efforts have been devoted to exploring innovative approaches for incorporating tunability to MAs, which is highly desirable because of the progressively increasing demand on designing versatile metadevices. Here, a comprehensive and systematical overview of active MAs with adaptive and on-demand manner is presented, highlighting innovative materials and unique strategies to precisely control the electromagnetic response. In addition to the mainstream method by manipulating periodic patterns, two additional approaches, including tailoring dielectric spacer and transforming overall structure are called back. Following this, key parameters, such as operating frequency, relative tuning range, and switching speed are summarized and compared to guide for optimum design. Finally, potential opportunities in the development of active MAs are discussed.
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Affiliation(s)
- Weiwei Li
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, P. R. China
- Shaanxi Key Laboratory of Flexible Electronics (KLoFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, P. R. China
| | - Manzhang Xu
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, P. R. China
- Shaanxi Key Laboratory of Flexible Electronics (KLoFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, P. R. China
| | - He-Xiu Xu
- Air and Missile Defense College, Air Force Engineering University, Xi'an, 710051, P. R. China
| | - Xuewen Wang
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, P. R. China
- Shaanxi Key Laboratory of Flexible Electronics (KLoFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, P. R. China
- MIIT Key Laboratory of Flexible Electronics (KLoFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, P. R. China
| | - Wei Huang
- Frontiers Science Center for Flexible Electronics (FSCFE) & Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, P. R. China
- Shaanxi Key Laboratory of Flexible Electronics (KLoFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, P. R. China
- MIIT Key Laboratory of Flexible Electronics (KLoFE), Northwestern Polytechnical University (NPU), 127 West Youyi Road, Xi'an, 710072, P. R. China
- State Key Laboratory of Organic Electronics and Information Displays, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, Nanjing, 210023, P. R. China
- Key Laboratory of Flexible Electronics(KLoFE)and Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211800, P. R. China
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16
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Zhang Y, Wu Z, Xia J, Wu J, Yang K, Dong C, Tong G, Zhang H, Yang R, Luo Y. Infrared metasurface absorber based on silicon-based CMOS process. OPTICS EXPRESS 2022; 30:32937-32947. [PMID: 36242345 DOI: 10.1364/oe.465680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/13/2022] [Indexed: 06/16/2023]
Abstract
Metasurface with metal-insulator-metal (MIM) structure has absorption properties for incident light at specific wavelengths. In this paper, we propose an infrared metasurface absorber based on silicon-based complementary metal oxide semiconductor (CMOS) process. By adding the prepared infrared metasurface absorber to the liquid crystal on silicon (LCoS) chip, it is used as the absorbing layer of LCoS configured between the pixel unit and the CMOS driver circuit. The effect of zero-order light caused by the gap between pixels in LCoS spatial light modulator (LCoS-SLM) on the light modulation function of the device is effectively reduced. Experiments show that the LCoS-SLM with infrared metasurface absorption structure can eliminate the zero-order light interference between the pixel gaps to a great extent and improve the modulation efficiency of the device. The proposed LCoS-SLM integrating infrared metasurface absorber structure based on silicon-based CMOS process has the advantages of low-cost and high modulation efficiency, which has high application value in the fields of holographic display, optical computing and optical communication.
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17
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Ihalage A, Hao Y. Formula Graph Self-Attention Network for Representation-Domain Independent Materials Discovery. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200164. [PMID: 35475548 PMCID: PMC9218748 DOI: 10.1002/advs.202200164] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 03/05/2022] [Indexed: 06/14/2023]
Abstract
The success of machine learning (ML) in materials property prediction depends heavily on how the materials are represented for learning. Two dominant families of material descriptors exist, one that encodes crystal structure in the representation and the other that only uses stoichiometric information with the hope of discovering new materials. Graph neural networks (GNNs) in particular have excelled in predicting material properties within chemical accuracy. However, current GNNs are limited to only one of the above two avenues owing to the little overlap between respective material representations. Here, a new concept of formula graph which unifies stoichiometry-only and structure-based material descriptors is introduced. A self-attention integrated GNN that assimilates a formula graph is further developed and it is found that the proposed architecture produces material embeddings transferable between the two domains. The proposed model can outperform some previously reported structure-agnostic models and their structure-based counterparts while exhibiting better sample efficiency and faster convergence. Finally, the model is applied in a challenging exemplar to predict the complex dielectric function of materials and nominate new substances that potentially exhibit epsilon-near-zero phenomena.
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Affiliation(s)
- Achintha Ihalage
- School of Electronic Engineering and Computer ScienceQueen Mary University of LondonMile End RdLondonE1 4NSUnited Kingdom
| | - Yang Hao
- School of Electronic Engineering and Computer ScienceQueen Mary University of LondonMile End RdLondonE1 4NSUnited Kingdom
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18
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Mansha S, Moitra P, Xu X, Mass TWW, Veetil RM, Liang X, Li SQ, Paniagua-Domínguez R, Kuznetsov AI. High resolution multispectral spatial light modulators based on tunable Fabry-Perot nanocavities. LIGHT, SCIENCE & APPLICATIONS 2022; 11:141. [PMID: 35581195 PMCID: PMC9114107 DOI: 10.1038/s41377-022-00832-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 04/11/2022] [Accepted: 04/29/2022] [Indexed: 06/01/2023]
Abstract
Spatial light modulators (SLMs) are the most relevant technology for dynamic wavefront manipulation. They find diverse applications ranging from novel displays to optical and quantum communications. Among commercial SLMs for phase modulation, Liquid Crystal on Silicon (LCoS) offers the smallest pixel size and, thus, the most precise phase mapping and largest field of view (FOV). Further pixel miniaturization, however, is not possible in these devices due to inter-pixel cross-talks, which follow from the high driving voltages needed to modulate the thick liquid crystal (LC) cells that are necessary for full phase control. Newly introduced metasurface-based SLMs provide means for pixel miniaturization by modulating the phase via resonance tuning. These devices, however, are intrinsically monochromatic, limiting their use in applications requiring multi-wavelength operation. Here, we introduce a novel design allowing small pixel and multi-spectral operation. Based on LC-tunable Fabry-Perot nanocavities engineered to support multiple resonances across the visible range (including red, green and blue wavelengths), our design provides continuous 2π phase modulation with high reflectance at each of the operating wavelengths. Experimentally, we realize a device with 96 pixels (~1 μm pitch) that can be individually addressed by electrical biases. Using it, we first demonstrate multi-spectral programmable beam steering with FOV~18° and absolute efficiencies exceeding 40%. Then, we reprogram the device to achieve multi-spectral lensing with tunable focal distance and efficiencies ~27%. Our design paves the way towards a new class of SLM for future applications in displays, optical computing and beyond.
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Affiliation(s)
- Shampy Mansha
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore, Singapore
| | - Parikshit Moitra
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore, Singapore
| | - Xuewu Xu
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore, Singapore
| | - Tobias W W Mass
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore, Singapore
| | - Rasna Maruthiyodan Veetil
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore, Singapore
| | - Xinan Liang
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore, Singapore
| | - Shi-Qiang Li
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore, Singapore
| | - Ramón Paniagua-Domínguez
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore, Singapore.
| | - Arseniy I Kuznetsov
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 138634, Singapore, Singapore.
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19
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Research of Gate-Tunable Phase Modulation Metasurfaces Based on Epsilon-Near-Zero Property of Indium-Tin-Oxide. PHOTONICS 2022. [DOI: 10.3390/photonics9050323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this paper, we proposed a reflection phase electrically tunable metasurface composed of an Au/Al2O3/ITO/Au grating structure. This antenna array can achieve a broad phase shift continuously and smoothly from 0° to 320° with a 5.85 V applied voltage bias. Tunability arises from field-effect modulation of the carrier concentrations or accumulation layer at the Al2O3/ITO interface, which excites electric and magnetic resonances in the epsilon-near-zero region. To make the reflected phase tuning range as wide as possible, some of the intensity of the reflected light is lost due to the excited surface plasmon effect. Simulation results show that the effect of optimal phase modulation can be realized at a wavelength range of 1550 nm by modulating the carrier concentration in our work. Additionally, we utilized an identical 13-unit array metasurface to demonstrate its application to the beam steering function. This active optical metasurface can enable a new realm of applications in ultrathin integrated photonic circuits.
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20
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Prakash S R, Kumar R, Mitra A. Reconfigurable and spectrally switchable perfect absorber based on a phase-change material. APPLIED OPTICS 2022; 61:2888-2897. [PMID: 35471366 DOI: 10.1364/ao.451285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
In this paper, we propose a lithography-free spectrally tunable prefect absorber based on an asymmetric Fabry-Perot cavity using Ge2Sb2Te5 (GST), a phase-change material, as the cavity layer. The proposed device shows a maximum absorption of 99.7% at 1550 nm, at a particular angle of incidence and polarization when the phase of GST is in the amorphous state. The absorption spectrum is spectrally switched to longer wavelength when the phase of GST is transformed from amorphous to crystalline. The tuning range is about 866 nm, and the maximum absorption is maintained above 99% in the whole tuning range. The crystallinity ratio of GST is varied by applying voltage pulses of different amplitudes and durations. The electrothermal cosimulations show that the phase change is obtained in the whole GST layer. Furthermore, by reamorphization of GST, the absorption spectrum can be switched back, enabling a reconfigurable perfect absorber. This work shows a viable path toward achieving a tunable perfect absorber covering a 1550 nm communication wavelength window as well as an emerging optical communication window around 2 µm wavelength.
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21
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Yang J, Gurung S, Bej S, Ni P, Howard Lee HW. Active optical metasurfaces: comprehensive review on physics, mechanisms, and prospective applications. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:036101. [PMID: 35244609 DOI: 10.1088/1361-6633/ac2aaf] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 09/28/2021] [Indexed: 06/14/2023]
Abstract
Optical metasurfaces with subwavelength thickness hold considerable promise for future advances in fundamental optics and novel optical applications due to their unprecedented ability to control the phase, amplitude, and polarization of transmitted, reflected, and diffracted light. Introducing active functionalities to optical metasurfaces is an essential step to the development of next-generation flat optical components and devices. During the last few years, many attempts have been made to develop tunable optical metasurfaces with dynamic control of optical properties (e.g., amplitude, phase, polarization, spatial/spectral/temporal responses) and early-stage device functions (e.g., beam steering, tunable focusing, tunable color filters/absorber, dynamic hologram, etc) based on a variety of novel active materials and tunable mechanisms. These recently-developed active metasurfaces show significant promise for practical applications, but significant challenges still remain. In this review, a comprehensive overview of recently-reported tunable metasurfaces is provided which focuses on the ten major tunable metasurface mechanisms. For each type of mechanism, the performance metrics on the reported tunable metasurface are outlined, and the capabilities/limitations of each mechanism and its potential for various photonic applications are compared and summarized. This review concludes with discussion of several prospective applications, emerging technologies, and research directions based on the use of tunable optical metasurfaces. We anticipate significant new advances when the tunable mechanisms are further developed in the coming years.
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Affiliation(s)
- Jingyi Yang
- Department of Physics & Astronomy, University of California, Irvine, CA 92697, United States of America
- Department of Physics, Baylor University, Waco, TX 76798, United States of America
| | - Sudip Gurung
- Department of Physics & Astronomy, University of California, Irvine, CA 92697, United States of America
- Department of Physics, Baylor University, Waco, TX 76798, United States of America
| | - Subhajit Bej
- Department of Physics, Baylor University, Waco, TX 76798, United States of America
| | - Peinan Ni
- Department of Physics, Baylor University, Waco, TX 76798, United States of America
| | - Ho Wai Howard Lee
- Department of Physics & Astronomy, University of California, Irvine, CA 92697, United States of America
- Department of Physics, Baylor University, Waco, TX 76798, United States of America
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22
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Xu X, Aggarwal D, Shankar K. Instantaneous Property Prediction and Inverse Design of Plasmonic Nanostructures Using Machine Learning: Current Applications and Future Directions. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:633. [PMID: 35214962 PMCID: PMC8874423 DOI: 10.3390/nano12040633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 02/06/2023]
Abstract
Advances in plasmonic materials and devices have given rise to a variety of applications in photocatalysis, microscopy, nanophotonics, and metastructures. With the advent of computing power and artificial neural networks, the characterization and design process of plasmonic nanostructures can be significantly accelerated using machine learning as opposed to conventional FDTD simulations. The machine learning (ML) based methods can not only perform with high accuracy and return optical spectra and optimal design parameters, but also maintain a stable high computing efficiency without being affected by the structural complexity. This work reviews the prominent ML methods involved in forward simulation and inverse design of plasmonic nanomaterials, such as Convolutional Neural Networks, Generative Adversarial Networks, Genetic Algorithms and Encoder-Decoder Networks. Moreover, we acknowledge the current limitations of ML methods in the context of plasmonics and provide perspectives on future research directions.
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Affiliation(s)
| | | | - Karthik Shankar
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada; (X.X.); (D.A.)
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23
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Zheng CY, Hadibrata W, Kim S, Schatz GC, Aydin K, Mirkin CA. Large-Area, Highly Crystalline DNA-Assembled Metasurfaces Exhibiting Widely Tunable Epsilon-Near-Zero Behavior. ACS NANO 2021; 15:18289-18296. [PMID: 34705417 DOI: 10.1021/acsnano.1c07496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Metasurfaces prepared via bottom-up nanoparticle assembly enable the deliberate manipulation of light in the optical regime, resulting in media with various engineered optical responses. Here, we report a scalable method to grow highly crystalline 2D metasurfaces composed of colloidal gold nanocubes, over macroscopic areas, using DNA-mediated assembly under equilibrium conditions. Using an effective medium description, we predict that these plasmonic metasurfaces behave as dielectric media with high refractive indices that can be dynamically tuned by tuning DNA length. Furthermore, we predict that, when coupled with an underlying thin gold film, the real permittivity of these metasurfaces exhibits a crossover region between positive and negative values, known as the epsilon-near-zero (ENZ) condition, which can be tuned between 1.5 and 2.6 μm by changing DNA length. Optical characterization performed on the DNA-assembled metasurfaces reveals that the predicted optical properties agree well with the measured response. Overall, we propose an efficient method for realizing large-area plasmonic metasurfaces that enable dynamic control over optical characteristics. High-index and ENZ metasurfaces operating in the telecommunications regime could have significant implications in high-speed optical computing, optical communications, optical imaging, and other areas.
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24
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Li M, Biswas S, Hail CU, Atwater HA. Refractive Index Modulation in Monolayer Molybdenum Diselenide. NANO LETTERS 2021; 21:7602-7608. [PMID: 34468150 DOI: 10.1021/acs.nanolett.1c02199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional transition metal dichalcogenides are promising candidates for ultrathin light modulators due to their highly tunable excitonic resonances at visible and near-infrared wavelengths. At cryogenic temperatures, large excitonic reflectivity in monolayer molybdenum diselenide (MoSe2) has been shown, but the permittivity and index modulation have not been studied. Here, we demonstrate large gate-tunability of complex refractive index in monolayer MoSe2 by Fermi level modulation and study the doping dependence of the A and B excitonic resonances for temperatures between 4 and 150 K. By tuning the charge density, we observe both temperature- and carrier-dependent epsilon-near-zero response in the permittivity and transition from metallic to dielectric near the A exciton energy. We attribute the dynamic control of the refractive index to the interplay between radiative and non-radiative decay channels that are tuned upon gating. Our results suggest the potential of monolayer MoSe2 as an active material for emerging photonics applications.
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Affiliation(s)
- Melissa Li
- Thomas J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Souvik Biswas
- Thomas J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Claudio U Hail
- Thomas J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Harry A Atwater
- Thomas J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, California 91125, United States
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25
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Castillo-Seoane J, Gil-Rostra J, López-Flores V, Lozano G, Javier Ferrer F, Espinós JP, Ostrikov K(K, Yubero F, González-Elipe AR, Barranco Á, Sánchez-Valencia JR, Borrás A. One-reactor vacuum and plasma synthesis of transparent conducting oxide nanotubes and nanotrees: from single wire conductivity to ultra-broadband perfect absorbers in the NIR. NANOSCALE 2021; 13:13882-13895. [PMID: 34477662 PMCID: PMC8374677 DOI: 10.1039/d1nr01937f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 07/05/2021] [Indexed: 06/13/2023]
Abstract
The eventual exploitation of one-dimensional nanomaterials needs the development of scalable, high yield, homogeneous and environmentally friendly methods capable of meeting the requirements for fabrication of functional nanomaterials with properties on demand. In this article, we demonstrate a vacuum and plasma one-reactor approach for the synthesis of fundamental common elements in solar energy and optoelectronics, i.e. the transparent conducting electrode but in the form of nanotube and nanotree architectures. Although the process is generic and can be used for a variety of TCOs and wide-bandgap semiconductors, we focus herein on indium doped tin oxide (ITO) as the most previously researched in previous applications. This protocol combines widely applied deposition techniques such as thermal evaporation for the formation of organic nanowires serving as 1D and 3D soft templates, deposition of polycrystalline layers by magnetron sputtering, and removal of the templates by simply annealing under mild vacuum conditions. The process variables are tuned to control the stoichiometry, morphology, and alignment of the ITO nanotubes and nanotrees. Four-probe characterization reveals the improved lateral connectivity of the ITO nanotrees and applied on individual nanotubes shows resistivities as low as 3.5 ± 0.9 × 10-4Ω cm, a value comparable to that of single-crystalline counterparts. The assessment of diffuse reflectance and transmittance in the UV-Vis range confirms the viability of the supported ITO nanotubes as random optical media working as strong scattering layers. Their further ability to form ITO nanotrees opens a path for practical applications as ultra-broadband absorbers in the NIR. The demonstrated low resistivity and optical properties of these ITO nanostructures open a way for their use in LEDs, IR shields, energy harvesting, nanosensors, and photoelectrochemical applications.
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Affiliation(s)
- Javier Castillo-Seoane
- Nanotechnology on Surfaces and Plasma Group, Materials Science Institute of Seville (ICMS), (Consejo Superior de Investigaciones Científicas (CSIC) – Universidad de Sevilla)C/Américo Vespucio 49Seville E-41092Spain
- Departamento de Física Atómica, Molecular y Nuclear (Universidad de Sevilla)Avda. Reina MercedesSeville E-41012Spain
| | - Jorge Gil-Rostra
- Nanotechnology on Surfaces and Plasma Group, Materials Science Institute of Seville (ICMS), (Consejo Superior de Investigaciones Científicas (CSIC) – Universidad de Sevilla)C/Américo Vespucio 49Seville E-41092Spain
| | - Víctor López-Flores
- Nanotechnology on Surfaces and Plasma Group, Materials Science Institute of Seville (ICMS), (Consejo Superior de Investigaciones Científicas (CSIC) – Universidad de Sevilla)C/Américo Vespucio 49Seville E-41092Spain
| | - Gabriel Lozano
- Multifunctional Optical Materials Group, Materials Science Institute of Seville (ICMS), (Consejo Superior de Investigaciones Científicas (CSIC) – Universidad de Sevilla)C/Américo Vespucio 49Seville E-41092Spain
| | - F. Javier Ferrer
- Centro Nacional de Aceleradores (Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (CSIC) and Junta de Andalucía)Av. Thomas A. Edison 7Seville E-41092Spain
| | - Juan P. Espinós
- Nanotechnology on Surfaces and Plasma Group, Materials Science Institute of Seville (ICMS), (Consejo Superior de Investigaciones Científicas (CSIC) – Universidad de Sevilla)C/Américo Vespucio 49Seville E-41092Spain
| | - Kostya (Ken) Ostrikov
- School of Chemistry and Physics, Queensland University of TechnologyBrisbaneQLD 4000Australia
- CSIRO-QUT Joint Sustainable Processes and Devices LaboratoryLindfieldNSW 2070Australia
| | - Francisco Yubero
- Nanotechnology on Surfaces and Plasma Group, Materials Science Institute of Seville (ICMS), (Consejo Superior de Investigaciones Científicas (CSIC) – Universidad de Sevilla)C/Américo Vespucio 49Seville E-41092Spain
| | - Agustín R. González-Elipe
- Nanotechnology on Surfaces and Plasma Group, Materials Science Institute of Seville (ICMS), (Consejo Superior de Investigaciones Científicas (CSIC) – Universidad de Sevilla)C/Américo Vespucio 49Seville E-41092Spain
| | - Ángel Barranco
- Nanotechnology on Surfaces and Plasma Group, Materials Science Institute of Seville (ICMS), (Consejo Superior de Investigaciones Científicas (CSIC) – Universidad de Sevilla)C/Américo Vespucio 49Seville E-41092Spain
| | - Juan R. Sánchez-Valencia
- Nanotechnology on Surfaces and Plasma Group, Materials Science Institute of Seville (ICMS), (Consejo Superior de Investigaciones Científicas (CSIC) – Universidad de Sevilla)C/Américo Vespucio 49Seville E-41092Spain
- Departamento de Física Atómica, Molecular y Nuclear (Universidad de Sevilla)Avda. Reina MercedesSeville E-41012Spain
| | - Ana Borrás
- Nanotechnology on Surfaces and Plasma Group, Materials Science Institute of Seville (ICMS), (Consejo Superior de Investigaciones Científicas (CSIC) – Universidad de Sevilla)C/Américo Vespucio 49Seville E-41092Spain
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26
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Wu J, Liu X, Fu H, Chang KC, Zhang S, Fu HY, Li Q. Manipulation of epsilon-near-zero wavelength for the optimization of linear and nonlinear absorption by supercritical fluid. Sci Rep 2021; 11:15936. [PMID: 34354198 PMCID: PMC8342460 DOI: 10.1038/s41598-021-95513-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/23/2021] [Indexed: 11/15/2022] Open
Abstract
We introduce supercritical fluid (SCF) technology to epsilon-near-zero (ENZ) photonics for the first time and experimentally demonstrate the manipulation of the ENZ wavelength for the enhancement of linear and nonlinear optical absorption in ENZ indium tin oxide (ITO) nanolayer. Inspired by the SCF's applications in repairing defects, reconnecting bonds, introducing dopants, and boosting the performance of microelectronic devices, here, this technique is used to exploit the influence of the electronic properties on optical characteristics. By reducing oxygen vacancies and electron scattering in the SCF oxidation process, the ENZ wavelength is shifted by 23.25 nm, the intrinsic loss is reduced by 20%, and the saturable absorption modulation depth is enhanced by > 30%. The proposed technique offers a time-saving low-temperature technique to optimize the linear and nonlinear absorption performance of plasmonics-based ENZ nanophotonic devices.
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Affiliation(s)
- Jiaye Wu
- School of Electronic and Computer Engineering, Peking University, Shenzhen, 518055, China
| | - Xuanyi Liu
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Haishi Fu
- School of Electronic and Computer Engineering, Peking University, Shenzhen, 518055, China
| | - Kuan-Chang Chang
- School of Electronic and Computer Engineering, Peking University, Shenzhen, 518055, China
| | - Shengdong Zhang
- School of Electronic and Computer Engineering, Peking University, Shenzhen, 518055, China
| | - H Y Fu
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Qian Li
- School of Electronic and Computer Engineering, Peking University, Shenzhen, 518055, China.
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27
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Liu C, Alam MZ, Pang K, Manukyan K, Hendrickson JR, Smith EM, Zhou Y, Reshef O, Song H, Zhang R, Song H, Alishahi F, Fallahpour A, Almaiman A, Boyd RW, Tur M, Willner AE. Tunable Doppler shift using a time-varying epsilon-near-zero thin film near 1550 nm. OPTICS LETTERS 2021; 46:3444-3447. [PMID: 34264234 DOI: 10.1364/ol.430106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
We experimentally investigate the tunable Doppler shift in an 80 nm thick indium-tin-oxide (ITO) film at its epsilon-near-zero (ENZ) region. Under strong and pulsed excitation, ITO exhibits a time-varying change in the refractive index. A maximum frequency redshift of 1.8 THz is observed in the reflected light when the pump light has a peak intensity of ∼140GW/cm2 and a pulse duration of ∼580fs, at an incident angle of 40°. The frequency shift increases with the increase in pump intensity and saturates at the intensity of ∼140GW/cm2. When the pump pulse duration increases from ∼580fs to ∼1380fs, the maximum attainable frequency shift decreases from 1.8 THz to 0.7 THz. In addition, the pump energy required to saturate the frequency shift decreases with the increase in pump pulse duration for ∼x<1ps and remains unchanged for ∼x>1ps durations. Tunability exists among the pump pulse energy, duration, and incident angle for the Doppler shift of the ITO-ENZ material, which can be employed to design efficient frequency shifters for telecom applications.
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28
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Xu D, Cui F, Zheng G. Dynamically Switchable Polarization-Independent Triple-Band Perfect Metamaterial Absorber Using a Phase-Change Material in the Mid-Infrared (MIR) Region. MICROMACHINES 2021; 12:mi12050548. [PMID: 34064884 PMCID: PMC8151617 DOI: 10.3390/mi12050548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/09/2021] [Accepted: 05/10/2021] [Indexed: 11/16/2022]
Abstract
A tunable metamaterial absorber (MMA) by reversible phase transitions in a mid-infrared regime is theoretically investigated. The absorber is composed of a molybdenum (Mo)-germanium-antimony-tellurium (Ge2Sb2Te5, GST)-Mo nanodisk structure superimposed on the GST-Al2O3 (aluminum oxide)-Mo film. Studies have shown that the combination of the inlaid metal-medium dielectric waveguide mode and the resonant cavity mode and the excitation of the propagating surface plasmon mode are the main reasons for the formation of the triple-band high absorption. Additionally, through the reversible phase change, the transition from high absorption to high reflection in the mid-infrared region is realized. The symmetry of the absorber eliminates the polarization dependence, and the near unity absorption efficiency can be maintained by incidence angles up to 60°. The presented method will enhance the functionality of the absorber and has the potential for the applications that require active control over light absorption.
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Affiliation(s)
- Dongdong Xu
- Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean, School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China; (D.X.); (F.C.)
| | - Fenping Cui
- Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean, School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China; (D.X.); (F.C.)
| | - Gaige Zheng
- Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean, School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, China; (D.X.); (F.C.)
- Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology (CICAEET), Nanjing University of Information Science & Technology, Nanjing 210044, China
- Correspondence:
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29
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Chowdhary AK, Bhowmik T, Gupta J, Sikdar D. Energy-saving all-weather window based on selective filtering of solar spectral radiation. APPLIED OPTICS 2021; 60:1315-1325. [PMID: 33690574 DOI: 10.1364/ao.412932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 01/11/2021] [Indexed: 06/12/2023]
Abstract
Passive all-weather windows, capable of selectively transmitting visible and infrared solar radiation, could help in bringing down fossil-fuel energy consumption globally by reducing the carbon footprint of typical air-conditioning systems for buildings and motor vehicles. Here, we report on designing metal-insulator-metal thin-films for application in passive windows, optimized for different climatic conditions. We analyze designs comprising different noble metals as well as their relatively inexpensive alternatives. By finding an optimal choice of materials and thicknesses of the metal and dielectric layers, our lithography-free simple design can provide all-weather solutions for passive windows with desired visible and infrared transmission/blocking capability. Obtained theoretical results agree well with full-wave simulations. Thus, our proposed designs enable developing low-cost, ultra-thin (thickness: 47-85 nm), polarization-independent, angle-insensitive (up to 83 deg), and large-area-compatible passive windows with improved solar-radiation control for different weather/climatic conditions. The figure-of-merit calculation shows that the relatively inexpensive metals used in our passive glasses can outperform industry-standard commercial glasses and previously reported infrared-blocking plasmonic glasses.
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30
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Wang W, Guan Z, Xu H. A high speed electrically switching reflective structural color display with large color gamut. NANOSCALE 2021; 13:1164-1171. [PMID: 33403380 DOI: 10.1039/d0nr07347d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Structural colors, which originate from the interactions between light and nanometer-scale structured materials, have the advantages of durability and environmentally friendly display compared with pigments and dyes. A large color gamut, high-speed, electrically-switching reflective structural color display is critical to dynamically tunable reflective structural color devices. Here, we report a theoretical design of an electrically switching reflective structural color display device with a large color gamut (∼157% sRGB, standard red green blue) and high speed (>10 MHz). Benefiting from the electric-switchable Epsilon-Near-Zero material and 1D dielectric grating with guided-mode resonance, the reflective display device can be electrically turned on or turned off by switching between a narrow band reflector and a transparent film. This design provides a promising solution towards reflective color displays, optical switches, spatial light modulators and so on.
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Affiliation(s)
- Wenqiang Wang
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China.
| | - Zhiqiang Guan
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China.
| | - Hongxing Xu
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China. and The Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
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31
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Park J, Jeong BG, Kim SI, Lee D, Kim J, Shin C, Lee CB, Otsuka T, Kyoung J, Kim S, Yang KY, Park YY, Lee J, Hwang I, Jang J, Song SH, Brongersma ML, Ha K, Hwang SW, Choo H, Choi BL. All-solid-state spatial light modulator with independent phase and amplitude control for three-dimensional LiDAR applications. NATURE NANOTECHNOLOGY 2021; 16:69-76. [PMID: 33106642 DOI: 10.1038/s41565-020-00787-y] [Citation(s) in RCA: 97] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 09/17/2020] [Indexed: 05/26/2023]
Abstract
Spatial light modulators are essential optical elements in applications that require the ability to regulate the amplitude, phase and polarization of light, such as digital holography, optical communications and biomedical imaging. With the push towards miniaturization of optical components, static metasurfaces are used as competent alternatives. These evolved to active metasurfaces in which light-wavefront manipulation can be done in a time-dependent fashion. The active metasurfaces reported so far, however, still show incomplete phase modulation (below 360°). Here we present an all-solid-state, electrically tunable and reflective metasurface array that can generate a specific phase or a continuous sweep between 0 and 360° at an estimated rate of 5.4 MHz while independently adjusting the amplitude. The metasurface features 550 individually addressable nanoresonators in a 250 × 250 μm2 area with no micromechanical elements or liquid crystals. A key feature of our design is the presence of two independent control parameters (top and bottom gate voltages) in each nanoresonator, which are used to adjust the real and imaginary parts of the reflection coefficient independently. To demonstrate this array's use in light detection and ranging, we performed a three-dimensional depth scan of an emulated street scene that consisted of a model car and a human figure up to a distance of 4.7 m.
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Affiliation(s)
- Junghyun Park
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea.
| | - Byung Gil Jeong
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Sun Il Kim
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Duhyun Lee
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Jungwoo Kim
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Changgyun Shin
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Chang Bum Lee
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Tatsuhiro Otsuka
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Jisoo Kyoung
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
- Department of Physics, Dankook University, Cheonan, Republic of Korea
| | - Sangwook Kim
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Ki-Yeon Yang
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Yong-Young Park
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Jisan Lee
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Inoh Hwang
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Jaeduck Jang
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Seok Ho Song
- Department of Physics, Hanyang University, Seoul, Republic of Korea
| | - Mark L Brongersma
- Geballe Lab for Advanced Materials, Stanford University, Stanford, CA, USA
| | - Kyoungho Ha
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Sung-Woo Hwang
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea
| | - Hyuck Choo
- Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Republic of Korea.
| | - Byoung Lyong Choi
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
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32
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Jin Y, Yu K. Broadband single-channel coherent perfect absorption with a perfect magnetic mirror. OPTICS EXPRESS 2020; 28:35108-35117. [PMID: 33182963 DOI: 10.1364/oe.408494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
Two-channel coherent perfect absorption (CPA) enables absorption modulation as well as perfect absorption in a very simple way. However, because of its narrow and discrete operable wavelength range, the CPA has been limited to specific applications. In this work, we theoretically and experimentally demonstrate broadband single-channel CPA operable from the visible to near-infrared wavelengths, using an ultrathin absorbing material on a pseudo perfect magnetic mirror. Our simple yet effective method can be applied to various applications such as solar cells, thermophotovoltaics, and stealth technology.
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33
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Yang T, Ding C, Ziolkowski RW, Guo YJ. A Controllable Plasmonic Resonance in a SiC-Loaded Single-Polarization Single-Mode Photonic Crystal Fiber Enables Its Application as a Compact LWIR Environmental Sensor. MATERIALS 2020; 13:ma13183915. [PMID: 32899734 PMCID: PMC7558795 DOI: 10.3390/ma13183915] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 12/31/2022]
Abstract
Near-perfect resonant absorption is attained in a single-polarization single-mode photonic crystal fiber (SPSM PCF) within the long-wave infrared (LWIR) range from 10 to 11 μm. The basic PCF design is a triangular lattice-based cladding of circular air holes and a core region augmented with rectangular slots. A particular set of air holes surrounding the core is partially filled with SiC, which exhibits epsilon near-zero (ENZ) and epsilon negative (ENG) properties within the wavelength range of interest. By tuning the configuration to have the fields of the unwanted fundamental and all higher order modes significantly overlap with the very lossy ENG rings, while the wanted fundamental propagating mode is concentrated in the core, the SPSM outcome is realized. Moreover, a strong plasmonic resonance is attained by adjusting the radii of the resulting cylindrical core-shell structures. The cause of the resonance is carefully investigated and confirmed. The resonance wavelength is shown to finely shift, depending on the relative permittivity of any material introduced into the PCF’s air holes, e.g., by flowing a liquid or gas in them. The potential of this plasmonic-based PCF structure as a very sensitive, short length LWIR spectrometer is demonstrated with an environmental monitoring application.
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34
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Kim SJ, Kim I, Choi S, Yoon H, Kim C, Lee Y, Choi C, Son J, Lee YW, Rho J, Lee B. Reconfigurable all-dielectric Fano metasurfaces for strong full-space intensity modulation of visible light. NANOSCALE HORIZONS 2020; 5:1088-1095. [PMID: 32377648 DOI: 10.1039/d0nh00139b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Dynamically reconfigurable nanoscale tuning of visible light properties is one of the ultimate goals both in the academic field of nanophotonics and the optics industry demanding compact and high-resolution display devices. Among various efforts incorporating actively reconfigurable optical materials into metamaterial structures, phase-change materials have been in the spotlight owing to their optical tunability in wide spectral regions including the visible spectrum. However, reconfigurable modulation of visible light intensity has been limited with small modulation depth, reflective schemes, and a lack of profound theoretical background for universal design rules. Here, all-dielectric phase-change Fano metasurface gratings are demonstrated for strong dynamic full-space (reflection and transmission) modulation of visible intensities based on Fano resonances. By judicious periodic couplings between densely arranged meta-atoms containing VO2, phase-change induced thermo-optic modulation of full-space intensities is highly enhanced in the visible spectrum. By providing intuitive design rules, we envision that the proposed study would contribute to nanophotonics-enabled optoelectronics technologies for imaging and sensing.
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Affiliation(s)
- Sun-Je Kim
- Inter-University Semiconductor Research Center and School of Electrical and Computer Engineering, Seoul National University, Gwanakro 1, Gwanak-Gu, Seoul 08826, Republic of Korea.
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35
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Meng Z, Cao H, Liu R, Wu X. An Electrically Tunable Dual-Wavelength Refractive Index Sensor Based on a Metagrating Structure Integrating Epsilon-Near-Zero Materials. SENSORS 2020; 20:s20082301. [PMID: 32316493 PMCID: PMC7219054 DOI: 10.3390/s20082301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/13/2020] [Accepted: 04/16/2020] [Indexed: 11/16/2022]
Abstract
In this paper, a reconfigurable sensing platform based on an asymmetrical metal-insulator-metal stacked structure integrating an indium tin oxide (ITO) ultrathin film is proposed and investigated numerically. The epsilon-near-zero (ENZ) mode and antisymmetric mode can be resonantly excited, generating near-perfect absorption of over 99.7% at 1144 and 1404 nm, respectively. The absorptivity for the ENZ mode can be modulated from 90.2% to 98.0% by varying the ENZ wavelength of ITO by applying different voltages. To obtain a highly sensitive biosensor, we show that the proposed structure has a full-width at half-maximum (FWHM) of 8.65 nm and a figure-of-merit (FOM) of 24.7 with a sensitivity of 213.3 nm/RI (refractive index) for the glucose solution. Our proposed device has potential for developing tunable biosensors for real-time health monitoring.
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Affiliation(s)
- Zhenya Meng
- School of Microelectronics and Communication Engineering, Chongqing University, Chongqing 400044, China
| | - Hailin Cao
- School of Microelectronics and Communication Engineering, Chongqing University, Chongqing 400044, China
- State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400044, China
- Correspondence:
| | - Run Liu
- School of Microelectronics and Communication Engineering, Chongqing University, Chongqing 400044, China
| | - Xiaodong Wu
- School of Microelectronics and Communication Engineering, Chongqing University, Chongqing 400044, China
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36
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Holsteen AL, Cihan AF, Brongersma ML. Temporal color mixing and dynamic beam shaping with silicon metasurfaces. Science 2020; 365:257-260. [PMID: 31320534 DOI: 10.1126/science.aax5961] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/20/2019] [Indexed: 01/16/2023]
Abstract
Metasurfaces offer the possibility to shape optical wavefronts with an ultracompact, planar form factor. However, most metasurfaces are static, and their optical functions are fixed after the fabrication process. Many modern optical systems require dynamic manipulation of light, and this is now driving the development of electrically reconfigurable metasurfaces. We can realize metasurfaces with fast (>105 hertz), electrically tunable pixels that offer complete (0- to 2π) phase control and large amplitude modulation of scattered waves through the microelectromechanical movement of silicon antenna arrays created in standard silicon-on-insulator technology. Our approach can be used to realize a platform technology that enables low-voltage operation of pixels for temporal color mixing and continuous, dynamic beam steering and light focusing.
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Affiliation(s)
- Aaron L Holsteen
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305-4045, USA
| | - Ahmet Fatih Cihan
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Mark L Brongersma
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305-4045, USA.
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37
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Seyedrezaei Z, Rejaei B, Memarian M. Frequency conversion and parametric amplification using a virtually rotating metasurface. OPTICS EXPRESS 2020; 28:6378-6394. [PMID: 32225887 DOI: 10.1364/oe.384467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/01/2020] [Indexed: 06/10/2023]
Abstract
We analyze the scattering of circularly polarized electromagnetic waves from a time-varying metasurface having a time-dependent surface susceptibility that locally mimics a rotating, anisotropic surface. Such virtually rotating metasurfaces (VRM) can be realized by means of electronically tunable surface elements and reach microwave-range rotation frequencies. It is shown that the scattered field contains the incident tone, as well as a single up-or down converted tone which differs by twice the rotation frequency of the surface. A simple full frequency converter is then proposed by augmenting the VRM with a metal screen separated by a proper distance. It is shown that after reflection from this system, the incident tone is fully converted to a single down- or up-converted tone, and shows amplification in the case of up conversion. The analysis of these time-rotating scenarios is carried out by switching to a rotating frame for the fields, leading to time-invariant equations, and thus using common phasor-representation. All results are also validated against an in-house 1D-FDTD code showing excellent agreement. A lumped element model using a 2D periodic metal mesh grid loaded with time-varying capacitive nodes is also presented that enables the VRM concept. This model is then further used to design a 3D realization, verified with static full-wave simulations for different values of the capacitor arrangement. Furthermore, the effect of piece-wise constant changes of surface susceptibility in a general virtually rotating metasurface is studied and it is shown to operate with acceptable results, which is of practical importance. The results of this paper can open new ways for realization of frequency conversion and amplification, in a magnetless and linear time-varying system.
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38
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Bruno V, Vezzoli S, DeVault C, Roger T, Ferrera M, Boltasseva A, Shalaev VM, Faccio D. Dynamical Control of Broadband Coherent Absorption in ENZ Films. MICROMACHINES 2020; 11:E110. [PMID: 31968578 PMCID: PMC7020079 DOI: 10.3390/mi11010110] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/13/2020] [Accepted: 01/16/2020] [Indexed: 11/17/2022]
Abstract
Interferometric effects between two counter-propagating beams incident on an optical system can lead to a coherent modulation of the absorption of the total electromagnetic radiation with 100% efficiency even in deeply subwavelength structures. Coherent perfect absorption (CPA) rises from a resonant solution of the scattering matrix and often requires engineered optical properties. For instance, thin film CPA benefits from complex nanostructures with suitable resonance, albeit at a loss of operational bandwidth. In this work, we theoretically and experimentally demonstrate a broadband CPA based on light-with-light modulation in epsilon-near-zero (ENZ) subwavelength films. We show that unpatterned ENZ films with different thicknesses exhibit broadband CPA with a near-unity maximum value located at the ENZ wavelength. By using Kerr optical nonlinearities, we dynamically tune the visibility and peak wavelength of the total energy modulation. Our results based on homogeneous thick ENZ media open a route towards on-chip devices that require efficient light absorption and dynamical tunability.
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Affiliation(s)
- Vincenzo Bruno
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Stefano Vezzoli
- The Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2BW, UK;
| | - Clayton DeVault
- Purdue Quantum Science and Engineering Institute, Purdue University, 1205 West State Street, West Lafayette, IN 47907, USA; (C.D.); (A.B.); (V.M.S.)
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, IN 47907, USA
| | - Thomas Roger
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK; (T.R.); (M.F.)
| | - Marcello Ferrera
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK; (T.R.); (M.F.)
| | - Alexandra Boltasseva
- Purdue Quantum Science and Engineering Institute, Purdue University, 1205 West State Street, West Lafayette, IN 47907, USA; (C.D.); (A.B.); (V.M.S.)
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, IN 47907, USA
| | - Vladimir M. Shalaev
- Purdue Quantum Science and Engineering Institute, Purdue University, 1205 West State Street, West Lafayette, IN 47907, USA; (C.D.); (A.B.); (V.M.S.)
- School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 1205 West State Street, West Lafayette, IN 47907, USA
| | - Daniele Faccio
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
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Lee CW, Choi HJ, Jeong H. Tunable metasurfaces for visible and SWIR applications. NANO CONVERGENCE 2020; 7:3. [PMID: 31956942 PMCID: PMC6970092 DOI: 10.1186/s40580-019-0213-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/03/2019] [Indexed: 05/17/2023]
Abstract
Demand on optical or photonic applications in the visible or short-wavelength infrared (SWIR) spectra, such as vision, virtual or augmented displays, imaging, spectroscopy, remote sensing (LIDAR), chemical reaction sensing, microscopy, and photonic integrated circuits, has envisaged new type of subwavelength-featured materials and devices for controlling electromagnetic waves. The study on metasurfaces, of which the thickness is either comparable to or smaller than the wavelength of the considered incoming electromagnetic wave, has been grown rapidly to embrace the needs of developing sub 100-micron active photonic pixelated devices and their arrayed form. Meta-atoms in metasurfaces are now actively controlled under external stimuli to lead to a large phase shift upon the incident light, which has provided a huge potential for arrayed two-dimensional active optics. This short review summarizes actively tunable or reconfigurable metasurfaces for the visible or SWIR spectra, to account for the physical operating principles and the current issues to overcome.
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Affiliation(s)
- Chang-Won Lee
- Institute of Advanced Optics and Photonics, Department of Applied Optics, Hanbat National University, Daejeon, 34158, Korea.
| | - Hee Jin Choi
- Institute of Advanced Optics and Photonics, Department of Applied Optics, Hanbat National University, Daejeon, 34158, Korea
| | - Heejeong Jeong
- Department of Physics, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
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40
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Kowerdziej R, Wróbel J, Kula P. Ultrafast electrical switching of nanostructured metadevice with dual-frequency liquid crystal. Sci Rep 2019; 9:20367. [PMID: 31889047 PMCID: PMC6937344 DOI: 10.1038/s41598-019-55656-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 11/28/2019] [Indexed: 11/13/2022] Open
Abstract
Shortening of switching times of various soft-matter-based tunable metamaterials is one of the key challenges to improve the functionality of modern active devices. Here we show an effective strategy in the evolution of soft-matter-based tunable metamaterials that makes possible acceleration of both on and off switching processes by using a dual-frequency liquid crystal mixture. The frequency-convertible dielectric anisotropy of the dual-frequency mixture enabled us to create a fast-response in-plane switching metasurface at the nanoscale, which could be tuned by an electrical signal with different frequencies. The results clearly show that the resonance of the metamaterial can be continuously and reversibly controlled within a wavelength range of 100 nm as the applied frequency is inverted between 1 kHz and 40 kHz, with a total response time (τ = τON + τOFF) of 1.89 ms. Furthermore, experimental characteristics of the hybrid metamaterial are in great agreement with numerical calculations, which allow us to anticipate active epsilon-near-zero behavior of the metadevice. This work indicates the future development direction of liquid-crystal-based active plasmonic systems.
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Affiliation(s)
- Rafał Kowerdziej
- Institute of Applied Physics, Military University of Technology, 2 Kaliskiego Str., 00-908, Warsaw, Poland.
| | - Jerzy Wróbel
- Institute of Physics, Polish Academy of Sciences, 32/46 Lotników Avenue, 02-668, Warsaw, Poland
| | - Przemysław Kula
- Institute of Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908, Warsaw, Poland
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41
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Shaltout AM, Shalaev VM, Brongersma ML. Spatiotemporal light control with active metasurfaces. Science 2019; 364:364/6441/eaat3100. [PMID: 31097638 DOI: 10.1126/science.aat3100] [Citation(s) in RCA: 212] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/17/2019] [Indexed: 12/15/2022]
Abstract
Optical metasurfaces have provided us with extraordinary ways to control light by spatially structuring materials. The space-time duality in Maxwell's equations suggests that additional structuring of metasurfaces in the time domain can even further expand their impact on the field of optics. Advances toward this goal critically rely on the development of new materials and nanostructures that exhibit very large and fast changes in their optical properties in response to external stimuli. New physics is also emerging as ultrafast tuning of metasurfaces is becoming possible, including wavelength shifts that emulate the Doppler effect, Lorentz nonreciprocity, time-reversed optical behavior, and negative refraction. The large-scale manufacturing of dynamic flat optics has the potential to revolutionize many emerging technologies that require active wavefront shaping with lightweight, compact, and power-efficient components.
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Affiliation(s)
- Amr M Shaltout
- Geballe Lab for Advanced Materials, Stanford University, Stanford, CA 94305, USA
| | - Vladimir M Shalaev
- Department of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47906, USA
| | - Mark L Brongersma
- Geballe Lab for Advanced Materials, Stanford University, Stanford, CA 94305, USA.
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42
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Li Y, van de Groep J, Talin AA, Brongersma ML. Dynamic Tuning of Gap Plasmon Resonances Using a Solid-State Electrochromic Device. NANO LETTERS 2019; 19:7988-7995. [PMID: 31560552 DOI: 10.1021/acs.nanolett.9b03143] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Plasmonic antennas and metasurfaces can effectively control light-matter interactions, and this facilitates a deterministic design of optical materials properties, including structural color. However, these optical properties are generally fixed after synthesis and fabrication, while many modern-day optics applications require active, low-power, and nonvolatile tuning. These needs have spurred broad research activities aimed at identifying materials and resonant structures capable of achieving large, dynamic changes in optical properties, especially in the challenging visible spectral range. In this work, we demonstrate dynamic tuning of polarization-dependent gap plasmon resonators that contain the electrochromic oxide WO3. Its refractive index in the visible changes continuously from n = 2.1 to 1.9 upon electrochemical lithium insertion and removal in a solid-state device. By incorporating WO3 into a gap plasmon resonator, the resonant wavelength can be shifted continuously and reversibly by up to 58 nm with less than 2 V electrochemical bias voltage. The resonator can remain in a tuned state for tens of minutes under open circuit conditions.
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Affiliation(s)
- Yiyang Li
- Sandia National Laboratories , Livermore , California 94550 , United States
- Department of Materials Science and Engineering , Stanford University , Stanford , California 94305 , United States
| | - Jorik van de Groep
- Geballe Laboratory of Advanced Materials , Stanford University , Stanford , California 94305 , United States
| | - A Alec Talin
- Sandia National Laboratories , Livermore , California 94550 , United States
| | - Mark L Brongersma
- Geballe Laboratory of Advanced Materials , Stanford University , Stanford , California 94305 , United States
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43
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Hu F, Jia W, Meng Y, Gong M, Yang Y. High-contrast optical switching using an epsilon-near-zero material coupled to a Bragg microcavity. OPTICS EXPRESS 2019; 27:26405-26414. [PMID: 31674523 DOI: 10.1364/oe.27.026405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/13/2019] [Indexed: 06/10/2023]
Abstract
Epsilon-near-zero (ENZ) materials have recently been suggested as excellent candidates for constructing all-optical and electro-optical switches in the infrared. The performance of previously reported ENZ material-based optical switches, however, has been greatly hampered by the low quality- (Q-) factor of the ENZ cavity, resulting in a large required optical pump fluence or applied voltage, a large insertion loss, or a small modulation depth. Here, we propose a solution by integrating the ENZ material into a Bragg microcavity, such that the Q-factor of the coupled cavity can be dramatically enhanced. Using high-mobility Dysprosium-doped cadmium oxide (CdO) as the prototype ENZ material, we numerically show an infrared all-optical switch with its reflectance modulated from near-zero to 94% under a pump fluence of only 7 μJ cm-2, about a 59-time-reduction compared with a state-of-the-art Berreman-type cavity. Moreover, the high-Q coupled cavity can also be adopted to realize a reflective electro-optical switch. Its reflectance can be switched from near-zero to 89%, with a bias electric field well below the breakdown field of conventional gate dielectrics. The switching operation can further be extended to the transmission mode with a slightly modified cavity geometry, with its absolute transmittance modulated by 40%.
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44
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Kim Y, Wu PC, Sokhoyan R, Mauser K, Glaudell R, Kafaie Shirmanesh G, Atwater HA. Phase Modulation with Electrically Tunable Vanadium Dioxide Phase-Change Metasurfaces. NANO LETTERS 2019; 19:3961-3968. [PMID: 31136191 DOI: 10.1021/acs.nanolett.9b01246] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We report a dynamically tunable reflectarray metasurface that continuously modulates the phase of reflected light in the near-infrared wavelength range under active electrical control of the phase transition from semiconducting to semimetallic states. We integrate a vanadium dioxide (VO2) active layer into the dielectric gap of antenna elements in a reflectarray metasurface, which undergoes an insulator-to-metal transition upon resistive heating of the metallic patch antenna. The induced phase transition in the VO2 film strongly perturbs the magnetic dipole resonance supported by the metasurface. By carefully controlling the volume fractions of coexisting metallic and dielectric regions of the VO2 film, we observe a continuous shift of the phase of the reflected light, with a maximal achievable phase shift as high as 250°. We also observe a reflectance modulation of 23.5% as well as a spectral shift of the resonance position by 175 nm. The metasurface phase modulation is fairly broadband, yielding large phase shifts at multiple operation wavelengths.
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45
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Vassant S, Hugonin JP, Greffet JJ. Quasi-confined ENZ mode in an anisotropic uniaxial thin slab. OPTICS EXPRESS 2019; 27:12317-12335. [PMID: 31052774 DOI: 10.1364/oe.27.012317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 03/21/2019] [Indexed: 06/09/2023]
Abstract
In this paper, we present a numerical modal study of a simple slab, made of an uniaxial anisotropic material having an "epsilon-near-zero" (ENZ) dielectric function, surrounded by vacuum. We use two Drude models with a different plasma frequency for the direction parallel and perpendicular to the slab surface as toy models to study the effect of uniaxial anisotropy of type I (∊‖ > 0, ∊⊥ < 0) and type II (∊‖ < 0, ∊⊥ > 0) on the different electromagnetic modes of the system. In addition to the so-called ENZ mode, studied in detail by Campione et. al [ Phys. Rev. B91, 121408(R) (2015)], the slab can support quasi-confined (QC) mode in the type I and type II anisotropy frequency ranges. We show that those modes exhibit a strong electric field enhancement, caused by the ENZ character of the dielectric function. In strong contrast with the ENZ mode, QC modes can have a strong electric field enhancement for thick slabs, with a Fabry-Perot-like electromagnetic field distribution spanning over the whole slab thickness. This opens the way for large electric field enhancement in thick slabs with QC ENZ modes. Thick slabs also allow metamaterial designs, giving the possibility to engineer the anisotropy of the effective dielectric function, opening interesting perspectives for the control of field enhancement of the ENZ QC modes and their integration in operating devices, such as detectors, sources, or modulators.
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46
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Runnerstrom EL, Kelley KP, Folland TG, Nolen JR, Engheta N, Caldwell JD, Maria JP. Polaritonic Hybrid-Epsilon-near-Zero Modes: Beating the Plasmonic Confinement vs Propagation-Length Trade-Off with Doped Cadmium Oxide Bilayers. NANO LETTERS 2019; 19:948-957. [PMID: 30582700 DOI: 10.1021/acs.nanolett.8b04182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Polaritonic materials that support epsilon-near-zero (ENZ) modes offer the opportunity to design light-matter interactions at the nanoscale through extreme subwavelength light confinement, producing phenomena like resonant perfect absorption. However, the utility of ENZ modes in nanophotonic applications has been limited by a flat spectral dispersion, which leads to small group velocities and extremely short propagation lengths. Here, we overcome this constraint by hybridizing ENZ and surface plasmon polariton (SPP) modes in doped cadmium oxide epitaxial bilayers. This results in strongly coupled hybrid modes that are characterized by an anticrossing in the polariton dispersion and a large spectral splitting on the order of 1/3 of the mode frequency. These hybrid modes simultaneously achieve modal propagation and ENZ mode-like interior field confinement, adding propagation character to ENZ mode properties. We subsequently tune the resonant frequencies, dispersion, and coupling of these polaritonic-hybrid-epsilon-near-zero (PH-ENZ) modes by tailoring the modal oscillator strength and the ENZ-SPP spectral overlap. PH-ENZ modes ultimately leverage the most desirable characteristics of both ENZ and SPP modes, allowing us to overcome the canonical plasmonic trade-off between confinement and propagation length.
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Affiliation(s)
- Evan L Runnerstrom
- Department of Materials Science and Engineering , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Kyle P Kelley
- Department of Materials Science and Engineering , North Carolina State University , Raleigh , North Carolina 27695 , United States
| | - Thomas G Folland
- Department of Mechanical Engineering , Vanderbilt University , Nashville , Tennessee 37212 , United States
| | - J Ryan Nolen
- Department of Mechanical Engineering , Vanderbilt University , Nashville , Tennessee 37212 , United States
- Interdisciplinary Materials Science Program , Vanderbilt University , Nashville , Tennessee 37212 , United States
| | - Nader Engheta
- Department of Electrical and Systems Engineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Joshua D Caldwell
- Department of Mechanical Engineering , Vanderbilt University , Nashville , Tennessee 37212 , United States
| | - Jon-Paul Maria
- Department of Materials Science and Engineering , North Carolina State University , Raleigh , North Carolina 27695 , United States
- Department of Materials Science and Engineering , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
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47
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Kim SJ, Choi S, Choi C, Lee Y, Sung J, Yun H, Jeong J, Mun SE, Lee YW, Lee B. Broadband efficient modulation of light transmission with high contrast using reconfigurable VO 2 diffraction grating. OPTICS EXPRESS 2018; 26:34641-34654. [PMID: 30650885 DOI: 10.1364/oe.26.034641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 12/10/2018] [Indexed: 06/09/2023]
Abstract
Ultra-compact dynamically reconfigurable modulation of optical transmission has been widely studied by using subwavelength-spaced resonant metasurface structures containing reconfigurable optical materials. However, it has been difficult to achieve high transmissivity, large modulation depth, and broad bandwidth simultaneously with the conventional resonance-based metasurface schemes. Here, we propose a reconfigurable phase-transition diffractive grating, made of thick VO2 ridge waveguides, for achieving the above-mentioned three goals simultaneously in the near-infrared range. Based on the large dielectric-to-plasmonic transition characteristic of VO2 in the near-infrared range, diffraction directivity of dual-VO2 ridge waveguide is designed to be tuned by thermally driven phase transition of VO2 for transverse electrically polarized illumination. Then, the diffractive VO2 ridge waveguide grating composed of the periodically arranged dual VO2 ridge waveguides is designed with on-state efficiency around 0.3 and minimum modulation depth about 0.35 over a broad bandwidth of 550 nm (1100-1650 nm). The working principle and excellent modulation performance are thoroughly verified through numerical and experimental studies.
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48
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Kim YB, Hwang DW, Moon YJ, Kim SK. Polarization-sensitive beam steering from quantum emitters coupled with birefringent metamaterials. APPLIED OPTICS 2018; 57:10271-10275. [PMID: 30645227 DOI: 10.1364/ao.57.010271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/12/2018] [Indexed: 06/09/2023]
Abstract
One-dimensional metal/dielectric subwavelength periodic patterns have dielectric or metallic material dispersions depending on the polarization of incident light. This feature enables the development of artificial, ultrathin, birefringent films. In this study, we report polarization-sensitive beam steering from quantum emitters coupled with one-dimensional metal/dielectric metamaterial films. Electromagnetic simulations show that an Al/ITO metamaterial film functioning as a quarter-wave plate leads to vertically directed radiation for one polarization and a saddle-shaped, diverging radiation pattern for the orthogonal polarization. The strategy studied herein is extended to achieve polarized, vertically directed emission from organic light-emitting diodes. A tailored Al/ITO metamaterial mirror yields an approximately 30-fold improvement in polarization ratio, in conjunction with polarization-dependent Purcell factor enhancement.
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49
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Park J, Kang JH, Liu X, Maddox SJ, Tang K, McIntyre PC, Bank SR, Brongersma ML. Dynamic thermal emission control with InAs-based plasmonic metasurfaces. SCIENCE ADVANCES 2018; 4:eaat3163. [PMID: 30539139 PMCID: PMC6286178 DOI: 10.1126/sciadv.aat3163] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 11/07/2018] [Indexed: 05/25/2023]
Abstract
Thermal emission from objects tends to be spectrally broadband, unpolarized, and temporally invariant. These common notions are now challenged with the emergence of new nanophotonic structures and concepts that afford on-demand, active manipulation of the thermal emission process. This opens a myriad of new applications in chemistry, health care, thermal management, imaging, sensing, and spectroscopy. Here, we theoretically propose and experimentally demonstrate a new approach to actively tailor thermal emission with a reflective, plasmonic metasurface in which the active material and reflector element are epitaxially grown, high-carrier-mobility InAs layers. Electrical gating induces changes in the charge carrier density of the active InAs layer that are translated into large changes in the optical absorption and thermal emission from metasurface. We demonstrate polarization-dependent and electrically controlled emissivity changes of 3.6%P (6.5% in relative scale) in the mid-infrared spectral range.
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Affiliation(s)
- Junghyun Park
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
| | - Ju-Hyung Kang
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
| | - Xiaoge Liu
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
| | - Scott J. Maddox
- Microelectronics Research Center and Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78758, USA
| | - Kechao Tang
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
| | - Paul C. McIntyre
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
| | - Seth R. Bank
- Microelectronics Research Center and Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78758, USA
| | - Mark L. Brongersma
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA
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50
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Lee Y, Kim SJ, Yun JG, Kim C, Lee SY, Lee B. Electrically tunable multifunctional metasurface for integrating phase and amplitude modulation based on hyperbolic metamaterial substrate. OPTICS EXPRESS 2018; 26:32063-32073. [PMID: 30650785 DOI: 10.1364/oe.26.032063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/13/2018] [Indexed: 06/09/2023]
Abstract
Active metasurfaces, which are tunable and reconfigurable nanophotonic structures with active materials, have been in spotlight as a versatile platform to control the profiles of scattered light. These nanoscale structures show surpassing functionalities compared to the conventional metasurfaces. They also play an important role in a wide range of applications for imaging, sensing, and data storage. Hence, the expansion of functionalities has been highly desired, in order to overcome the limited space constraints and realize the integration of several optical devices on a single compact platform. In this context, an electrically tunable metasurface that enables respective modulation of the phase and amplitude of reflected light, depending on the angle of incidence at the targeted wavelength, is proposed. This resonance-based device with hyperbolic metamaterial substrate excites different kinds of highly confined modes, according to the incident angle. Indium tin oxide is employed to offer electrically tunable optical properties in the near-infrared regime. At the wavelength of 1450 nm, the proposed device modulates the phase of reflected light with ~207 degrees of modulation depth for normal incidence, whereas it shows ~86% of relative reflectance change for oblique incidence of 60 degrees. In principle, the proposed scheme might provide a path to applications for the next-generation ultracompact integrated systems.
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