1
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Chai R, Liu W, Li Z, Zhang Y, Wang H, Cheng H, Tian J, Chen S. Spatial Information Lasing Enabled by Full-k-Space Bound States in the Continuum. PHYSICAL REVIEW LETTERS 2024; 132:183801. [PMID: 38759196 DOI: 10.1103/physrevlett.132.183801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 04/03/2024] [Indexed: 05/19/2024]
Abstract
Optical amplification and massive information transfer in modern physics depend on stimulated radiation. However, regardless of traditional macroscopic lasers or emerging micro- and nanolasers, the information modulations are generally outside the lasing cavities. On the other hand, bound states in the continuum (BICs) with inherently enormous Q factors are limited to zero-dimensional singularities in momentum space. Here, we propose the concept of spatial information lasing, whose lasing information entropy can be correspondingly controlled by near-field Bragg coupling of guided modes. This concept is verified in gain-loss metamaterials supporting full-k-space BICs with both flexible manipulations and strong confinement of light fields. The counterintuitive high-dimensional BICs exist in a continuous energy band, which provide a versatile platform to precisely control each lasing Fourier component and, thus, can directly convey rich spatial information on the compact size. Single-mode operation achieved in our scheme ensures consistent and stable lasing information. Our findings can be expanded to different wave systems and open new scenarios in informational coherent amplification and high-Q physical frameworks for both classical and quantum applications.
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Affiliation(s)
- Ruoheng Chai
- The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Institute of Applied Physics, Nankai University, Tianjin 300071, China
| | - Wenwei Liu
- The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Institute of Applied Physics, Nankai University, Tianjin 300071, China
| | - Zhancheng Li
- The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Institute of Applied Physics, Nankai University, Tianjin 300071, China
| | - Yuebian Zhang
- The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Institute of Applied Physics, Nankai University, Tianjin 300071, China
| | - Haonan Wang
- The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Institute of Applied Physics, Nankai University, Tianjin 300071, China
| | - Hua Cheng
- The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Institute of Applied Physics, Nankai University, Tianjin 300071, China
| | - Jianguo Tian
- The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Institute of Applied Physics, Nankai University, Tianjin 300071, China
| | - Shuqi Chen
- The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Institute of Applied Physics, Nankai University, Tianjin 300071, China
- School of Materials Science and Engineering, Smart Sensing Interdisciplinary Science Center, Nankai University, Tianjin 300350, China
- The Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
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2
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Zhi J, Qiu Z, Wang X, Huang K, Xu B. Versatile polarization-converted non-diffractive Bessel beams based on fully phase-modulated metasurfaces. OPTICS EXPRESS 2024; 32:11560-11572. [PMID: 38571000 DOI: 10.1364/oe.520030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 03/05/2024] [Indexed: 04/05/2024]
Abstract
The Bessel beam has become significant in optical research due to its properties such as a long focal depth, self-healing, and non-diffraction. However, conventional methods for generating Bessel beams have drawbacks such as limited flexibility and tunability and the use of bulky optics. These factors lead to the complexity of the optical systems. This paper presents what we believe is a novel approach to generating Bessel beams by utilizing a fully phase-modulated all-dielectric metasurface. The proposed method enables the arbitrary and independent manipulation of cross-polarized and co-polarized components, allowing the creation of Bessel beams featuring multiple polarization conversions when subjected to left-handed circularly polarized (LCP) incidence. To demonstrate the versatility and effectiveness of the method, three metasurfaces with distinct characteristics are designed. The simulated generated Bessel beams exhibit qualities including long focal depth, non-diffraction behavior, self-healing capabilities, and polarization conversion, which align with the theoretical predictions. This work presents novel possibilities for effectively generating and multi-functional application of Bessel beams.
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3
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Mason S, Meretska ML, Spägele C, Ossiander M, Capasso F. Metasurface-Controlled Holographic Microcavities. ACS PHOTONICS 2024; 11:941-949. [PMID: 38523748 PMCID: PMC10958604 DOI: 10.1021/acsphotonics.3c01479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/30/2024] [Accepted: 01/30/2024] [Indexed: 03/26/2024]
Abstract
Optical microcavities confine light to wavelength-scale volumes and are a key component for manipulating and enhancing the interaction of light, vacuum states, and matter. Current microcavities are constrained to a small number of spatial mode profiles. Imaging cavities can accommodate complicated modes but require an externally preshaped input. Here, we experimentally demonstrate a visible-wavelength, metasurface-based holographic microcavity that overcomes these limitations. The micrometer-scale metasurface cavity fulfills the round-trip condition for a designed mode with a complex-shaped intensity profile and thus selectively enhances light that couples to this mode, achieving a spectral bandwidth of 0.8 nm. By imaging the intracavity mode, we show that the holographic mode changes quickly with the cavity length and that the cavity displays the desired spatial mode profile only close to the design cavity length. When a metasurface is placed on a distributed Bragg reflector and steep phase gradients are realized, the correct choice of the reflector's top layer material can boost metasurface performance considerably. The applied forward-design method can be readily transferred to other spectral regimes and mode profiles.
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Affiliation(s)
- Sydney Mason
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Maryna Leonidivna Meretska
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Christina Spägele
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Marcus Ossiander
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Institute of Experimental Physics, Graz University of Technology, 8010 Graz, Austria
| | - Federico Capasso
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
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4
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Mao X, Yu G, Zhao Y, Wei B, Li Z, Yang F, Wang X. Design and simulation of an extreme ultraviolet metalens based on the Pancharatnam-Berry phase. APPLIED OPTICS 2024; 63:1867-1874. [PMID: 38437291 DOI: 10.1364/ao.511899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 02/06/2024] [Indexed: 03/06/2024]
Abstract
Extreme ultraviolet (EUV) radiation plays a key role in the fields of material science, attosecond metrology, and lithography. However, the reflective optical components typically used in EUV systems contribute to their bulky size, weight, and increased costs for fabrication. In this paper, we theoretically investigate transmissive metalens designs capable of focusing the EUV light based on the Pancharatnam-Berry phase. The designed metalens is composed of nanoscale elliptical holes, which can guide and manipulate EUV light due to the higher refractive index of the vacuum holes compared to that of the surrounding material. We designed an EUV metalens with a diameter of 10 µm, which supports a focal length of 24 µm and a numerical aperture of up to 0.2. It can focus 55-nm EUV incident light to a diffraction-limited spot, and the focusing efficiency is calculated to be as high as about 7% over a broad EUV frequency range (50-65 nm). This study reveals the possibility of applying a dielectric metalens in the EUV region without a transmissive optical material.
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Lee D, Chen WW, Wang L, Chan YC, Chen W. Data-Driven Design for Metamaterials and Multiscale Systems: A Review. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2305254. [PMID: 38050899 DOI: 10.1002/adma.202305254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/15/2023] [Indexed: 12/07/2023]
Abstract
Metamaterials are artificial materials designed to exhibit effective material parameters that go beyond those found in nature. Composed of unit cells with rich designability that are assembled into multiscale systems, they hold great promise for realizing next-generation devices with exceptional, often exotic, functionalities. However, the vast design space and intricate structure-property relationships pose significant challenges in their design. A compelling paradigm that could bring the full potential of metamaterials to fruition is emerging: data-driven design. This review provides a holistic overview of this rapidly evolving field, emphasizing the general methodology instead of specific domains and deployment contexts. Existing research is organized into data-driven modules, encompassing data acquisition, machine learning-based unit cell design, and data-driven multiscale optimization. The approaches are further categorized within each module based on shared principles, analyze and compare strengths and applicability, explore connections between different modules, and identify open research questions and opportunities.
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Affiliation(s)
- Doksoo Lee
- Dept. of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Wei Wayne Chen
- J. Mike Walker '66 Department of Mechanical Engineering, Texas A&M University, College Station, TX, 77840, USA
| | - Liwei Wang
- Dept. of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Yu-Chin Chan
- Siemens Corporation, Technology, Princeton, NJ, 08540, USA
| | - Wei Chen
- Dept. of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
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6
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Mason S, Benea-Chelmus IC. Hybrid silicon-organic Huygens' metasurface for phase modulation. OPTICS EXPRESS 2023; 31:36161-36170. [PMID: 38017771 DOI: 10.1364/oe.504216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 10/02/2023] [Indexed: 11/30/2023]
Abstract
Spatial light modulators have desirable applications in sensing and free space communication because they create an interface between the optical and electronic realms. Electro-optic modulators allow for high-speed intensity manipulation of an electromagnetic wavefront. However, most surfaces of this sort pose limitations due to their ability to modulate intensity rather than phase. Here we investigate an electro-optic modulator formed from a silicon-organic Huygens' metasurface. In a simulation-based study, we discover a metasurface design immersed in high-performance electro-optic molecules that can achieve near-full resonant transmission with phase coverage over the full 2π range. Through the electro-optic effect, we show 140 ∘ (0.79π) modulation over a range of -100 to 100 V at 1330 nm while maintaining near-constant transmitted field intensity (between 0.66 and 0.8). These results potentiate the fabrication of a high-speed spatial light modulator with the resolved parameters.
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7
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Sisombat F, Devaux T, Haumesser L, Callé S. Contactless deformation of fluid interfaces by acoustic radiation pressure. Sci Rep 2023; 13:14703. [PMID: 37679368 PMCID: PMC10485005 DOI: 10.1038/s41598-023-39464-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 07/26/2023] [Indexed: 09/09/2023] Open
Abstract
Reversible and programmable shaping of surfaces promises wide-ranging applications in tunable optics and acoustic metasurfaces. Based on acoustic radiation pressure, contactless and real-time deformation of fluid interface can be achieved. This paper presents an experimental and numerical study to characterize the spatiotemporal properties of the deformation induced by acoustic radiation pressure. Using localized ultrasonic excitation, we report the possibility of on-demand tailoring of the induced protrusion at water-air interface in space and time, depending on the shape of the input pressure field. The experimental method used to measure the deformation of the water surface in space and time shows close agreement with simulations. We demonstrate that acoustic radiation pressure allows shaping protrusion at fluid interfaces, which could be changed into a various set of spatiotemporal distributions, considering simple parameters of the ultrasonic excitation. This paves the way for novel approach to design programmable space and time-dependent gratings at fluid interfaces.
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Affiliation(s)
- Félix Sisombat
- GREMAN UMR 7347, Université de Tours, INSA CVL, CNRS, 41000, Blois, France.
| | - Thibaut Devaux
- GREMAN UMR 7347, Université de Tours, INSA CVL, CNRS, 41000, Blois, France
| | - Lionel Haumesser
- GREMAN UMR 7347, Université de Tours, INSA CVL, CNRS, 41000, Blois, France
| | - Samuel Callé
- GREMAN UMR 7347, Université de Tours, INSA CVL, CNRS, 41000, Blois, France
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8
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Li WF, Arya G, Roques-Carmes C, Lin Z, Johnson SG, Soljačić M. Transcending shift-invariance in the paraxial regime via end-to-end inverse design of freeform nanophotonics. OPTICS EXPRESS 2023; 31:24260-24272. [PMID: 37475257 DOI: 10.1364/oe.492553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 05/28/2023] [Indexed: 07/22/2023]
Abstract
Traditional optical elements and conventional metasurfaces obey shift-invariance in the paraxial regime. For imaging systems obeying paraxial shift-invariance, a small shift in input angle causes a corresponding shift in the sensor image. Shift-invariance has deep implications for the design and functionality of optical devices, such as the necessity of free space between components (as in compound objectives made of several curved surfaces). We present a method for nanophotonic inverse design of compact imaging systems whose resolution is not constrained by paraxial shift-invariance. Our method is end-to-end, in that it integrates density-based full-Maxwell topology optimization with a fully iterative elastic-net reconstruction algorithm. By the design of nanophotonic structures that scatter light in a non-shift-invariant manner, our optimized nanophotonic imaging system overcomes the limitations of paraxial shift-invariance, achieving accurate, noise-robust image reconstruction beyond shift-invariant resolution.
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9
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Sebek M, Thanh NTK, Su X, Teng J. A Genetic Algorithm for Universal Optimization of Ultrasensitive Surface Plasmon Resonance Sensors with 2D Materials. ACS OMEGA 2023; 8:20792-20800. [PMID: 37323412 PMCID: PMC10268016 DOI: 10.1021/acsomega.3c01387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/09/2023] [Indexed: 06/17/2023]
Abstract
We present a general optimization technique for surface plasmon resonance, (SPR) yielding a range of ultrasensitive SPR sensors from a materials database with an enhancement of ∼100%. Applying the algorithm, we propose and demonstrate a novel dual-mode SPR structure coupling SPP and a waveguide mode within GeO2 featuring an anticrossing behavior and an unprecedented sensitivity of 1364 deg/RIU. An SPR sensor operating at wavelengths of 633 nm having a bimetal Al/Ag structure sandwiched between hBN can achieve a sensitivity of 578 deg/RIU. For a wavelength of 785 nm, we optimized a sensor as a Ag layer sandwiched between hBN/MoS2/hBN heterostructures achieving a sensitivity of 676 deg/RIU. Our work provides a guideline and general technique for the design and optimization of high sensitivity SPR sensors for various sensing applications in the future.
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Affiliation(s)
- Matej Sebek
- UCL
Healthcare Biomagnetics and Nanomaterials Laboratories, 21 Albemarle Street, London W1S 4BS, United Kingdom
- Institute
of Materials Research and Engineering, Agency for Science, Technology and Research, Innovis, Singapore 138634 Singapore
- Biophysics
Group, Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Nguyen Thi Kim Thanh
- UCL
Healthcare Biomagnetics and Nanomaterials Laboratories, 21 Albemarle Street, London W1S 4BS, United Kingdom
- Biophysics
Group, Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Xiaodi Su
- Institute
of Materials Research and Engineering, Agency for Science, Technology and Research, Innovis, Singapore 138634 Singapore
| | - Jinghua Teng
- Institute
of Materials Research and Engineering, Agency for Science, Technology and Research, Innovis, Singapore 138634 Singapore
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10
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Ossiander M, Meretska ML, Hampel HK, Lim SWD, Knefz N, Jauk T, Capasso F, Schultze M. Extreme ultraviolet metalens by vacuum guiding. Science 2023; 380:59-63. [PMID: 37023199 DOI: 10.1126/science.adg6881] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Extreme ultraviolet (EUV) radiation is a key technology for material science, attosecond metrology, and lithography. Here, we experimentally demonstrate metasurfaces as a superior way to focus EUV light. These devices exploit the fact that holes in a silicon membrane have a considerably larger refractive index than the surrounding material and efficiently vacuum-guide light with a wavelength of ~50 nanometers. This allows the transmission phase at the nanoscale to be controlled by the hole diameter. We fabricated an EUV metalens with a 10-millimeter focal length that supports numerical apertures of up to 0.05 and used it to focus ultrashort EUV light bursts generated by high-harmonic generation down to a 0.7-micrometer waist. Our approach introduces the vast light-shaping possibilities provided by dielectric metasurfaces to a spectral regime that lacks materials for transmissive optics.
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Affiliation(s)
- Marcus Ossiander
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Maryna Leonidivna Meretska
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Hana Kristin Hampel
- Institute of Experimental Physics, Graz University of Technology, 8010 Graz, Austria
| | - Soon Wei Daniel Lim
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Nico Knefz
- Institute of Experimental Physics, Graz University of Technology, 8010 Graz, Austria
| | - Thomas Jauk
- Institute of Experimental Physics, Graz University of Technology, 8010 Graz, Austria
| | - Federico Capasso
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Martin Schultze
- Institute of Experimental Physics, Graz University of Technology, 8010 Graz, Austria
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11
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So S, Kim J, Badloe T, Lee C, Yang Y, Kang H, Rho J. Multicolor and 3D Holography Generated by Inverse-Designed Single-Cell Metasurfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208520. [PMID: 36575136 DOI: 10.1002/adma.202208520] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/17/2022] [Indexed: 05/17/2023]
Abstract
Metasurface-generated holography has emerged as a promising route for fully reproducing vivid scenes by manipulating the optical properties of light using ultra-compact devices. However, achieving multiple holographic images using a single metasurface is still difficult due to the capacity limit of a single meta-atom. In this work, an inverse design method based on gradient-descent optimization is presented to encode multiple pieces of holographic information into a single metasurface. The proposed method allows the inverse design of single-cell metasurfaces without the need for complex meta-atom design strategies, facilitating high-throughput fabrication using broadband low-loss materials. By exploiting the proposed design method, both multiplane red-green-blue (RGB) color and three-dimensional (3D) holograms are designed and experimentally demonstrated. Multiplane RGB color holograms with nine distinct holograms are achieved, which demonstrate the state-of-the-art data capacity of a phase-only metasurface. The first experimental demonstration of metasurface-generated 3D holograms with completely independent and distinct images in each plane is also presented. The current research findings provide a viable route for practical metasurface-generated holography by demonstrating the high-density holography produced by a single metasurface. It is expected to ultimately lead to optical storage, display, and full-color imaging applications.
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Affiliation(s)
- Sunae So
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Graduate School of Artificial Intelligence, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Department of Electro-Mechanical Systems Engineering, Korea University, Sejong, 30019, Republic of Korea
| | - Joohoon Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Trevon Badloe
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Graduate School of Artificial Intelligence, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Chihun Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Younghwan Yang
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Hyunjung Kang
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Junsuk Rho
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
- POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics, Pohang, 37673, Republic of Korea
- National Institute of Nanomaterials Technology (NINT), Pohang, 37673, Republic of Korea
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Abstract
Cavities concentrate light and enhance its interaction with matter. Confining to microscopic volumes is necessary for many applications but space constraints in such cavities limit the design freedom. Here we demonstrate stable optical microcavities by counteracting the phase evolution of the cavity modes using an amorphous Silicon metasurface as cavity end mirror. Careful design allows us to limit the metasurface scattering losses at telecom wavelengths to less than 2% and using a distributed Bragg reflector as metasurface substrate ensures high reflectivity. Our demonstration experimentally achieves telecom-wavelength microcavities with quality factors of up to 4600, spectral resonance linewidths below 0.4 nm, and mode volumes below [Formula: see text]. The method introduces freedom to stabilize modes with arbitrary transverse intensity profiles and to design cavity-enhanced hologram modes. Our approach introduces the nanoscopic light control capabilities of dielectric metasurfaces to cavity electrodynamics and is industrially scalable using semiconductor manufacturing processes.
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13
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Cai J, Yu H. Full-space wavefront manipulation enabled by asymmetric photonic spin-orbit interactions. OPTICS EXPRESS 2023; 31:1409-1419. [PMID: 36785176 DOI: 10.1364/oe.477883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/28/2022] [Indexed: 06/18/2023]
Abstract
Optical metasurfaces empower complete wavefront manipulation of electromagnetic waves and have been found in extensive applications, whereas most of them work in either transmission or reflection space. Here, we demonstrate that two independent and arbitrary phase profiles in transmission and reflection spaces could be produced by a monolayer all-dielectric metasurface based on the asymmetric photonic spin-orbit interactions, realizing full-space wavefront independent manipulation. Furthermore, the supercell-based non-local approach is employed to suppress crosstalk between adjacent nanopillars in one supercell for broadband and high-efficiency wavefront manipulation in full space. Compared with the conventional unit cell-based local approach, such a method could improve efficiency about 10%. As a proof of concept, two metadevices are designed, in which the maximum diffraction efficiencies are ∼95.53%/∼74.07% within the wavelength range of 1500-1600 nm in reflection/transmission space under circularly polarized light incidence. This configuration may offer an efficient way for 2π-space holographic imaging, augmented reality, virtual reality technologies, three-dimensional imaging, and so forth.
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14
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Xu H, Cheng J, Ji Y, Fan F, Chang S. Coaxial dual-beam wavefront shaping using nonlocal diffractive metasurfaces in terahertz frequencies. OPTICS LETTERS 2023; 48:469-472. [PMID: 36638486 DOI: 10.1364/ol.476985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
Metasurfaces for wavefront shaping rely on local phase modulation in subwavelength unit cells, which show limited degree of freedom in dealing with complex and multiple beam transformation. Here, we assign multiple beams into different diffraction orders coaxially located along the same direction, whose wavefronts are tailored by optimizing the diffraction coefficients in two orders and two polarization states of a supercell. By evenly splitting the energy into two orders and adjusting the zeroth-order diffraction phase, a Bessel beam and a vortex beam are simultaneously generated in the near field and far field along a coaxial direction. The effectiveness of the method is validated by the excellent agreement between the simulation and experimental characterization of the two beams.
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15
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Single-shot 3D imaging with point cloud projection based on metadevice. Nat Commun 2022; 13:7842. [PMID: 36543781 PMCID: PMC9772337 DOI: 10.1038/s41467-022-35483-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
Three-dimensional (3D) imaging is a crucial information acquisition technology for light detection, autonomous vehicles, gesture recognition, machine vision, and other applications. Metasurface, as a subwavelength scale two-dimensional array, offers flexible control of optical wavefront owing to abundant design freedom. Metasurfaces are promising for use as optical devices because they have large field of view and powerful functionality. In this study, we propose a flat optical device based on a single-layer metasurface to project a coded point cloud in the Fourier space and explore a sophisticated matching algorithm to achieve 3D reconstruction, offering a complete technical roadmap for single-shot detection. We experimentally demonstrate that the depth accuracy of our system is smaller than 0.24 mm at a measurement distance of 300 mm, indicating the feasibility of the submillimetre measurement platform. Our method can pave the way for practical applications such as surface shape detection, gesture recognition, and personal authentication.
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16
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Zhang X, Huang L, Zhao R, Zhou H, Li X, Geng G, Li J, Li X, Wang Y, Zhang S. Basis function approach for diffractive pattern generation with Dammann vortex metasurfaces. SCIENCE ADVANCES 2022; 8:eabp8073. [PMID: 36197982 PMCID: PMC9534505 DOI: 10.1126/sciadv.abp8073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
In mathematics, general functions can be decomposed into a linear combination of basis functions. This principle can be used for creating an infinite number of distinct geometric patterns based on a finite number of basis patterns. Here, we propose a Dammann vortex metasurface (DVM) for optically generating an array of diverse, diffraction-multiplexed vortex patterns, based on three custom-defined basis patterns. The proposed DVM, with its capability of quantitatively correlating phase and intensity distribution in different diffraction orders, opens up doors for various applications including orbital angular momentum encryptions and quantum entanglement.
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Affiliation(s)
- Xue Zhang
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Lingling Huang
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
- Corresponding author. (L.H.); (Y.W.); (S.Z.)
| | - Ruizhe Zhao
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Hongqiang Zhou
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Xin Li
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Guangzhou Geng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100191, China
| | - Junjie Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100191, China
| | - Xiaowei Li
- Laser Micro/Nano-Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Yongtian Wang
- Beijing Engineering Research Center of Mixed Reality and Advanced Display, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
- Corresponding author. (L.H.); (Y.W.); (S.Z.)
| | - Shuang Zhang
- Department of Physics, University of Hong Kong, Hong Kong, China
- Department of Electrical and Electronic Engineering, University of Hong Kong, Hong Kong, China
- Corresponding author. (L.H.); (Y.W.); (S.Z.)
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17
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Ni X, Luan H, Kim JT, Rogge SI, Bai Y, Kwak JW, Liu S, Yang DS, Li S, Li S, Li Z, Zhang Y, Wu C, Ni X, Huang Y, Wang H, Rogers JA. Soft shape-programmable surfaces by fast electromagnetic actuation of liquid metal networks. Nat Commun 2022; 13:5576. [PMID: 36151092 PMCID: PMC9508113 DOI: 10.1038/s41467-022-31092-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 06/01/2022] [Indexed: 11/15/2022] Open
Abstract
Low modulus materials that can shape-morph into different three-dimensional (3D) configurations in response to external stimuli have wide-ranging applications in flexible/stretchable electronics, surgical instruments, soft machines and soft robotics. This paper reports a shape-programmable system that exploits liquid metal microfluidic networks embedded in an elastomer matrix, with electromagnetic forms of actuation, to achieve a unique set of properties. Specifically, this materials structure is capable of fast, continuous morphing into a diverse set of continuous, complex 3D surfaces starting from a two-dimensional (2D) planar configuration, with fully reversible operation. Computational, multi-physics modeling methods and advanced 3D imaging techniques enable rapid, real-time transformations between target shapes. The liquid-solid phase transition of the liquid metal allows for shape fixation and reprogramming on demand. An unusual vibration insensitive, dynamic 3D display screen serves as an application example of this type of morphable surface. Low modulus materials that can change shape in response to external stimuli are promising for a wide range of applications. The authors here introduce a shape-reprogrammable construct, based on liquid metal microfluidic networks and electromagnetic actuation, that supports a unique collection of capabilities.
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Affiliation(s)
- Xinchen Ni
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA
| | - Haiwen Luan
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA
| | - Jin-Tae Kim
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA
| | - Sam I Rogge
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA
| | - Yun Bai
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA.,Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA.,Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA
| | - Jean Won Kwak
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA.,Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA
| | - Shangliangzi Liu
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA
| | - Da Som Yang
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA
| | - Shuo Li
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA
| | - Shupeng Li
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA
| | - Zhengwei Li
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA
| | - Yamin Zhang
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA
| | - Changsheng Wu
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA
| | - Xiaoyue Ni
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA. .,Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA. .,Department of Biostatistics and Bioinformatics, Duke University, Durham, NC, USA.
| | - Yonggang Huang
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA. .,Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA. .,Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA. .,Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA.
| | - Heling Wang
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA. .,Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA. .,Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA.
| | - John A Rogers
- Querrey Simpson Institute for Bioelectronics, Northwestern University, Evanston, IL, USA. .,Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA. .,Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA. .,Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA. .,Department of Neurological Surgery, Northwestern University, Evanston, IL, USA. .,Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL, USA. .,Department of Chemistry, Northwestern University, Evanston, IL, USA.
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18
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Malek SC, Overvig AC, Alù A, Yu N. Multifunctional resonant wavefront-shaping meta-optics based on multilayer and multi-perturbation nonlocal metasurfaces. LIGHT, SCIENCE & APPLICATIONS 2022; 11:246. [PMID: 35922413 PMCID: PMC9349264 DOI: 10.1038/s41377-022-00905-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 06/11/2022] [Accepted: 06/20/2022] [Indexed: 05/22/2023]
Abstract
Photonic devices rarely provide both elaborate spatial control and sharp spectral control over an incoming wavefront. In optical metasurfaces, for example, the localized modes of individual meta-units govern the wavefront shape over a broad bandwidth, while nonlocal lattice modes extended over many unit cells support high quality-factor resonances. Here, we experimentally demonstrate nonlocal dielectric metasurfaces in the near-infrared that offer both spatial and spectral control of light, realizing metalenses focusing light exclusively over a narrowband resonance while leaving off-resonant frequencies unaffected. Our devices attain this functionality by supporting a quasi-bound state in the continuum encoded with a spatially varying geometric phase. We leverage this capability to experimentally realize a versatile platform for multispectral wavefront shaping where a stack of metasurfaces, each supporting multiple independently controlled quasi-bound states in the continuum, molds the optical wavefront distinctively at multiple wavelengths and yet stay transparent over the rest of the spectrum. Such a platform is scalable to the visible for applications in augmented reality and transparent displays.
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Affiliation(s)
- Stephanie C Malek
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA
| | - Adam C Overvig
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, 10031, USA
| | - Andrea Alù
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, 10031, USA
- Physics Program, Graduate Center, City University of New York, New York, NY, 10016, USA
| | - Nanfang Yu
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA.
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19
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Active multiband varifocal metalenses based on orbital angular momentum division multiplexing. Nat Commun 2022; 13:4292. [PMID: 35879316 PMCID: PMC9314414 DOI: 10.1038/s41467-022-32044-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 07/14/2022] [Indexed: 11/14/2022] Open
Abstract
Metalenses as miniature flat lenses exhibit a substantial potential in replacing traditional optical component. Although the metalenses have been intensively explored, their functions are limited by poor active ability, narrow operating band and small depth of field (DOF). Here, we show a dielectric metalens consisting of TiO2 nanofins array with ultrahigh aspect ratio to realize active multiband varifocal function. Regulating the orbital angular momentum (OAM) by the phase assignment covering the 2π range, its focal lengths can be switched from 5 mm to 35 mm. This active optical multiplexing uses the physical properties of OAM channels to selectively address and decode the vortex beams. The multiband capability and large DOFs with conversion efficiency of 49% for this metalens are validated for both 532 nm and 633 nm, and the incidence wavelength can further change the focal lengths. This non-mechanical tunable metalens demonstrates the possibility of active varifocal metalenses. A dielectric metalens consisting of ultrahigh aspect ratio TiO2 nanofins array is demonstrated to realize active multiband varifocal functionality. By regulating the orbital angular momentum, the focal length can be switched from 5 mm to 35 mm with large DOFs.
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20
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Elastic Metagratings with Simultaneous Modulation of Reflected and Transmitted Waves. CRYSTALS 2022. [DOI: 10.3390/cryst12070901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Elastic metagratings enabling independent and complete control of both reflection and transmission of bulk longitudinal and transverse waves are highly desired in application scenarios such as non-destructive assessment and structural health monitoring. In this work, we propose a kind of simply structured metagrating composed only of elliptical hollow cylinders carved periodically in a steel background. By utilizing the grating diffraction theory and genetic algorithm, we endow these metagratings with the attractive functionality of simultaneous and high-efficiency modulation of every reflection and transmission channel of both longitudinal and transverse waves. Interesting wave-front manipulation effects including pure mode conversion and anomalous deflection along the desired direction are clearly demonstrated through full-wave numerical simulations. Due to its subwavelength thickness and high manipulation efficiency, the proposed metagrating is expected to be useful in the design of multifunctional elastic planar devices.
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21
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Cheng J, Yang Y, Fan F, Wang X, Chang S. Terahertz tight-focused Bessel beam generation and point-to-point focusing based on nonlocal diffraction engineering. OPTICS LETTERS 2022; 47:2879-2882. [PMID: 35648954 DOI: 10.1364/ol.460747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
Metasurfaces transform the wavefront by spatially varying the amplitude or phase of the incoming beam. Instead of encoding such variation by subwavelength unit cells, it is achievable over diffraction engineering of supercell structures, which outperforms the unit-cell method when the spatial gradient is large. In addition to tight focusing, here we apply this method to achieve plane wave-to-Bessel beam transformation and point-to-point focusing at terahertz frequencies. The Bessel beam has a small beam waist (0.57λ) and long depth of focus (9.1λ) for subwavelength-resolution imaging over a long distance. The point-to-point focusing changes the divergence angle from 16° to 70°. Both devices are validated by numerical simulations and experimental results with good agreement.
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22
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Dang PT, Kim J, Lee JH. Negative dispersion of a form birefringence in subwavelength gratings. OPTICS EXPRESS 2022; 30:18287-18299. [PMID: 36221633 DOI: 10.1364/oe.458322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/03/2022] [Indexed: 06/16/2023]
Abstract
An achromatic response is required in most optical systems for wideband and straightforward configurations. The chromatic response of the optical system depends on the optical dispersion of the elements in the system. Here we study the dispersion of subwavelength grating (SWG) known to have a form birefringence. The birefringence of SWG was numerically analyzed with Bloch wave analysis (BWA) and finite element method (FEM). The sandwiched SWG with two identical substrates was studied for practical applications. We successfully demonstrated the negative dispersion form birefringence of SWG with an optimal duty cycle. This extraordinary dispersion was also shown considering the intrinsic dispersion of materials. Dispersion- and the angular response were in a tradeoff relationship while they depended on periodicity. The optical interference between the grating and the substrates can be eliminated by controlling the duty cycle. Our analysis offers optimal SWG with achromatic birefringence and high transparency, promising in the widespread applications of polarization control devices.
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23
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Abstract
Flat optics has emerged as a key player in the area of structured light and its applications, owing to its subwavelength resolution, ease of integration, and compact footprint. Although its first generation has revolutionized conventional lenses and enabled anomalous refraction, new classes of meta-optics can now shape light and dark features of an optical field with an unprecedented level of complexity and multifunctionality. Here, we review these efforts with a focus on metasurfaces that use different properties of input light-angle of incidence and direction, polarization, phase distribution, wavelength, and nonlinear behavior-as optical knobs for tuning the output response. We discuss ongoing advances in this area as well as future challenges and prospects. These recent developments indicate that optically tunable flat optics is poised to advance adaptive camera systems, microscopes, holograms, and portable and wearable devices and may suggest new possibilities in optical communications and sensing.
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Affiliation(s)
- Ahmed H Dorrah
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Federico Capasso
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
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24
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Zhu X, Engelberg J, Remennik S, Zhou B, Pedersen JN, Uhd Jepsen P, Levy U, Kristensen A. Resonant Laser Printing of Optical Metasurfaces. NANO LETTERS 2022; 22:2786-2792. [PMID: 35311279 DOI: 10.1021/acs.nanolett.1c04874] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
One of the challenges for metasurface research is upscaling. The conventional methods for fabrication of metasurfaces, such as electron-beam or focused ion beam lithography, are not scalable. The use of ultraviolet steppers or nanoimprinting still requires large-size masks or stamps, which are costly and challenging in further handling. This work demonstrates a cost-effective and lithography-free method for printing optical metasurfaces. It is based on resonant absorption of laser light in an optical cavity formed by a multilayer structure of ultrathin metal and dielectric coatings. A nearly perfect light absorption is obtained via interferometric control of absorption and operating around a critical coupling condition. Controlled by the laser power, the surface undergoes a structural transition from random, semiperiodic, and periodic to amorphous patterns with nanoscale precision. The reliability, upscaling, and subwavelength resolution of this approach are demonstrated by realizing metasurfaces for structural colors, optical holograms, and diffractive optical elements.
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Affiliation(s)
- Xiaolong Zhu
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Jacob Engelberg
- Department of Applied Physics, The Faculty of Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Sergei Remennik
- Department of Applied Physics, The Faculty of Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Binbin Zhou
- Department of Photonics Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Jonas Nyvold Pedersen
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Peter Uhd Jepsen
- Department of Photonics Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Uriel Levy
- Department of Applied Physics, The Faculty of Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Anders Kristensen
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby 2800, Denmark
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25
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Zhang H, Zhang Z, Ma XI, Pu M, Li X, Guo Y, Luo X. Polarization multiplexing metasurface for dual-band achromatic focusing. OPTICS EXPRESS 2022; 30:12069-12079. [PMID: 35473136 DOI: 10.1364/oe.454805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
We propose a dual-band achromatic focusing metasurface based on polarization multiplexing and dispersion engineering. An anisotropic resonant phase meta-atom is designed to realize independent nonlinear phase manipulation along the orthogonal directions. Achromatic focusing metasurface and broadband reflectarray antenna are further constructed in the microwave region with a computer-assisted particle swarm optimization algorithm. The standard deviation of focus offset at 11-16 GHz (for x-polarization) and 18-24 GHz (for y-polarization) are compressed to 19.83% and 16.60% of the dispersive metasurface, respectively. The radiation gains of the reflectarray antenna increase by an average of 19.49 dB and 15.08 dB in the broadband region compared with the bare standard rectangle waveguides. Furthermore, such an achromatic metasurface can be utilized to realize different functions with polarization selectivity and applied to other frequency ranges, which holds great promise in integrated optics.
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26
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Ye ZT, Ho WT, Chen CH. Highly Reflective Thin-Film Optimization for Full-Angle Micro-LEDs. NANOSCALE RESEARCH LETTERS 2021; 16:152. [PMID: 34628557 PMCID: PMC8502190 DOI: 10.1186/s11671-021-03611-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/29/2021] [Indexed: 05/30/2023]
Abstract
Displays composed of micro-light-emitting diodes (micro-LEDs) are regarded as promising next-generation self-luminous screens and have advantages such as high contrast, high brightness, and high color purity. The luminescence of such a display is similar to that of a Lambertian light source. However, owing to reduction in the light source area, traditional secondary optical lenses are not suitable for adjusting the light field types of micro-LEDs and cause problems that limit the application areas. This study presents the primary optical designs of dielectric and metal films to form highly reflective thin-film coatings with low absorption on the light-emitting surfaces of micro-LEDs to optimize light distribution and achieve full-angle utilization. Based on experimental results with the prototype, that have kept low voltage variation rates, low optical losses characteristics, and obtain the full width at half maximum (FWHM) of the light distribution is enhanced to 165° and while the center intensity is reduced to 63% of the original value. Hence, a full-angle micro-LEDs with a highly reflective thin-film coating are realized in this work. Full-angle micro-LEDs offer advantages when applied to commercial advertising displays or plane light source modules that require wide viewing angles.
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Affiliation(s)
- Zhi-Ting Ye
- Department of Mechanical Engineering, Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, 168, University Rd., Min-Hsiung, Chia-Yi, 62102, Taiwan.
| | - Wen-Tsung Ho
- Department of R&D, General Manager's Office, TO2M Corporation, Hsinchu, 30010, Taiwan
| | - Chia-Hui Chen
- Department of Mechanical Engineering, Advanced Institute of Manufacturing with High-Tech Innovations, National Chung Cheng University, 168, University Rd., Min-Hsiung, Chia-Yi, 62102, Taiwan
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