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Xie P, Deng Y, Ding Q, Zheng X, Zhou Z, Kivshar Y, Wang W. Strong Coupling of Resonant Metasurfaces with Epsilon-Near-Zero Guided Modes. NANO LETTERS 2024; 24:9027-9033. [PMID: 38984823 DOI: 10.1021/acs.nanolett.4c02158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
We study, both theoretically and experimentally, strong interaction between a quasi-bound state in the continuum (QBIC) supported by a resonant metasurface with an epsilon-near-zero (ENZ) guided mode excited in an ultrathin ITO layer. We observe and quantify the strong coupling regime of the QBIC-ENZ interaction in the hybrid metasurface manifested through the mode splitting over 200 meV. We also measure experimentally the resonant nonlinear response enhanced near the ENZ frequency and observe the effective nonlinear refractive index up to ∼4 × 10-13 m2/W in the ITO-integrated dielectric nanoresonators, which provides a promising platform for low-power nonlinear photonic devices.
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Affiliation(s)
- Peng Xie
- College of Physics, Sichuan University, Chengdu 610065, China
- Nonlinear Physics Center, Research School of Physics, Australian National University, Canberra Australian Capital Territory 2601, Australia
| | - Yanhui Deng
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Qi Ding
- College of Physics, Sichuan University, Chengdu 610065, China
- School of Engineering, Westlake University, Hangzhou 310030, China
| | - Xiaorui Zheng
- School of Engineering, Westlake University, Hangzhou 310030, China
| | - Zhangkai Zhou
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou 510275, China
| | - Yuri Kivshar
- Nonlinear Physics Center, Research School of Physics, Australian National University, Canberra Australian Capital Territory 2601, Australia
| | - Wei Wang
- College of Physics, Sichuan University, Chengdu 610065, China
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Wang H, Hu Z, Deng J, Zhang X, Chen J, Li K, Li G. All-optical ultrafast polarization switching with nonlinear plasmonic metasurfaces. SCIENCE ADVANCES 2024; 10:eadk3882. [PMID: 38381825 PMCID: PMC10881032 DOI: 10.1126/sciadv.adk3882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 01/17/2024] [Indexed: 02/23/2024]
Abstract
Optical switching has important applications in optical information processing, optical computing, and optical communications. The long-term pursuit of optical switch is to achieve short switching time and large modulation depth. Among various mechanisms, all-optical switching based on Kerr effect represents a promising solution. However, it is usually difficult to compromise both switching time and modulation depth of a Kerr-type optical switch. To circumvent this constraint, symmetry selective polarization switching via second-harmonic generation (SHG) in nonlinear crystals has been attracting scientists' attention. Here, we demonstrate SHG-based all-optical ultrafast polarization switching by using geometric phase controlled nonlinear plasmonic metasurfaces. A switching time of hundreds of femtoseconds and a modulation depth of 97% were experimentally demonstrated. The function of dual-channel all-optical switching was also demonstrated on a metasurface, which consists of spatially variant meta-atoms. The nonlinear metasurface proposed here represents an important platform for developing all-optical ultrafast switches and would benefit the area of optical information processing.
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Affiliation(s)
- Heng Wang
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zixian Hu
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Junhong Deng
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xuecai Zhang
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jiafei Chen
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Kingfai Li
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Guixin Li
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Institute for Applied Optics and Precision Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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Yang G, Allen MS, Allen JW, Harutyunyan H. Unlocking Efficient Ultrafast Bound-Electron Optical Nonlinearities via Mirror Induced Quasi Bound States in the Continuum. NANO LETTERS 2024; 24:1679-1686. [PMID: 38262062 PMCID: PMC10853962 DOI: 10.1021/acs.nanolett.3c04431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/18/2024] [Accepted: 01/19/2024] [Indexed: 01/25/2024]
Abstract
The operation of photonic devices often relies on modulation of their refractive index. While the sub-bandgap index change through bound-electron optical nonlinearity offers a faster response than utilizing free carriers with an overbandgap pump, optical switching often suffers from inefficiency. Here, we use a recently observed metasurface based on mirror-induced optical bound states in the continuum, to enable superior modulation characteristics. We achieve a pulsewidth-limited switching time of 100 fs, reflectance change of 22%, remarkably low energy consumption of 255 μJ/cm2, and an enhancement of modulation contrast by a factor of 440 compared to unpatterned silicon. Additionally, the narrow photonic resonance facilitates the detection of the dispersive nondegenerate two-photon nonlinearity, allowing tunable pump and probe excitation. These findings are explained by a two-band theoretical model for the dispersive nonlinear index. The demonstrated efficient and rapid switching holds immense potential for applications, including quantum photonics, sensing, and metrology.
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Affiliation(s)
- Guoce Yang
- Department
of Physics, Emory University, Atlanta, Georgia 30322, United States
| | - Monica S. Allen
- Air
Force Research Laboratory, Munitions Directorate, Eglin AFB, Florida 32542, United States
| | - Jeffery W. Allen
- Air
Force Research Laboratory, Munitions Directorate, Eglin AFB, Florida 32542, United States
| | - Hayk Harutyunyan
- Department
of Physics, Emory University, Atlanta, Georgia 30322, United States
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Karimi M, Awan KM, Vaddi Y, Alaee R, Upham J, Alam MZ, Boyd RW. Interactions of Fundamental Mie Modes with Thin Epsilon-near-Zero Substrates. NANO LETTERS 2023; 23:11555-11561. [PMID: 38038228 DOI: 10.1021/acs.nanolett.3c03301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Extensive research has focused on Mie modes in dielectric nanoresonators, enabling the creation of thin optical devices surpassing their bulk counterparts. This study investigates the interactions between two fundamental Mie modes, electric and magnetic dipoles, and the epsilon-near-zero (ENZ) mode. Analytical, simulation, and experimental analyses reveal that the presence of the ENZ substrate significantly modifies these modes despite a large size mismatch. Electric and magnetic dipole modes, both with ∼12 THz line widths, exhibit 21 and 26 THz anticrossings, respectively, when coupled to the ENZ mode, indicating strong coupling. We also demonstrate that this strongly coupled system yields notably large subpicosecond nonlinear responses. Our results establish a solid foundation for designing functional, nonlinear, dynamic dielectric metasurfaces with ENZ materials.
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Affiliation(s)
- Mohammad Karimi
- Department of Electrical and Computer Engineering, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
| | - Kashif Masud Awan
- Institute of Materials Science and Engineering, Washington University in Saint Louis, St. Louis, Missouri 63130, United States
| | - Yaswant Vaddi
- Department of Physics, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
| | - Rasoul Alaee
- Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology, Wolfgang-Gaede-Str. 1, 76131, Karlsruhe, Germany
| | - Jeremy Upham
- Department of Physics, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
| | - M Zahirul Alam
- Department of Physics, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
| | - Robert W Boyd
- Department of Physics, University of Ottawa, Ottawa, ON, Canada, K1N 6N5
- Institute of Optics, University of Rochester, 275 Hutchison Rd, Wilmot Bldg, Rochester, New York 14620, United States
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Choudhary S, Iqbal S, Karimi M, Reshef O, Alam MZ, Boyd RW. Strongly Coupled Plasmon Polaritons in Gold and Epsilon-Near-Zero Bifilms. ACS PHOTONICS 2023; 10:162-169. [PMID: 36691428 PMCID: PMC9853859 DOI: 10.1021/acsphotonics.2c01412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Indexed: 06/17/2023]
Abstract
Epsilon-near-zero (ENZ) polaritons in a thin transparent conducting-oxide film exhibit a significant electric field enhancement and localization within the film at frequencies close to their plasma frequency, but do not propagate. Meanwhile, plasmon polariton modes in thin metallic films can propagate for several microns, but are more loosely confined in the metal. Here, we propose a strongly coupled bilayered structure of a thin gold film on a thin indium tin oxide (ITO) film that supports hybrid polariton modes. We experimentally characterize the dispersion of these modes and show that they have propagation lengths of 4-8 μm while retaining mode confinement greater than that of the polariton in gold films by nearly an order of magnitude. We study the tunability of this coupling strength by varying the thickness of the ITO film and show that ultrastrong coupling is possible at certain thicknesses. The unusual linear and nonlinear optical properties of ITO at ENZ frequencies make these bifilms useful for the active tuning of strong coupling, ultrafast switching, and enhanced nonlinear interactions at near-infrared frequencies.
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Affiliation(s)
- Saumya Choudhary
- Institute
of Optics, University of Rochester, Rochester, New York14627, United States
| | - Saleem Iqbal
- Institute
of Optics, University of Rochester, Rochester, New York14627, United States
| | - Mohammad Karimi
- Department
of Physics, University of Ottawa, Ottawa, OntarioK1N 6N5, Canada
| | - Orad Reshef
- Department
of Physics, University of Ottawa, Ottawa, OntarioK1N 6N5, Canada
| | - M. Zahirul Alam
- Department
of Physics, University of Ottawa, Ottawa, OntarioK1N 6N5, Canada
| | - Robert W. Boyd
- Institute
of Optics, University of Rochester, Rochester, New York14627, United States
- Department
of Physics, University of Ottawa, Ottawa, OntarioK1N 6N5, Canada
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Tan WJ, Thomas PA, Barnes WL. Origin of an Anticrossing between a Leaky Photonic Mode and an Epsilon-Near-Zero Point of Silver. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:19262-19267. [PMID: 36425000 PMCID: PMC9677423 DOI: 10.1021/acs.jpcc.2c05836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 10/10/2022] [Indexed: 06/16/2023]
Abstract
Strong light-matter coupling hybridizes light and matter to form states known as polaritons, which give rise to a characteristic anticrossing signature in dispersion plots. Here, we identify conditions under which an anticrossing can occur in the absence of strong coupling. We study planar silver/dielectric structures and find that, around the epsilon-near-zero point in silver, the impedance matching between the silver and dielectric layers gives rise to an anticrossing. Our work shows that care must be taken to ensure that anticrossing arising from impedance matching is not misattributed to strong coupling.
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