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Zhong H, He T, Meng Y, Xiao Q. Photonic Bound States in the Continuum in Nanostructures. MATERIALS (BASEL, SWITZERLAND) 2023; 16:7112. [PMID: 38005042 PMCID: PMC10672634 DOI: 10.3390/ma16227112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/02/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023]
Abstract
Bound states in the continuum (BIC) have garnered considerable attention recently for their unique capacity to confine electromagnetic waves within an open or non-Hermitian system. Utilizing a variety of light confinement mechanisms, nanostructures can achieve ultra-high quality factors and intense field localization with BIC, offering advantages such as long-living resonance modes, adaptable light control, and enhanced light-matter interactions, paving the way for innovative developments in photonics. This review outlines novel functionality and performance enhancements by synergizing optical BIC with diverse nanostructures, delivering an in-depth analysis of BIC designs in gratings, photonic crystals, waveguides, and metasurfaces. Additionally, we showcase the latest advancements of BIC in 2D material platforms and suggest potential trajectories for future research.
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Affiliation(s)
| | | | | | - Qirong Xiao
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China; (H.Z.); (T.H.); (Y.M.)
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Meng Y, Zhong H, Xu Z, He T, Kim JS, Han S, Kim S, Park S, Shen Y, Gong M, Xiao Q, Bae SH. Functionalizing nanophotonic structures with 2D van der Waals materials. NANOSCALE HORIZONS 2023; 8:1345-1365. [PMID: 37608742 DOI: 10.1039/d3nh00246b] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The integration of two-dimensional (2D) van der Waals materials with nanostructures has triggered a wide spectrum of optical and optoelectronic applications. Photonic structures of conventional materials typically lack efficient reconfigurability or multifunctionality. Atomically thin 2D materials can thus generate new functionality and reconfigurability for a well-established library of photonic structures such as integrated waveguides, optical fibers, photonic crystals, and metasurfaces, to name a few. Meanwhile, the interaction between light and van der Waals materials can be drastically enhanced as well by leveraging micro-cavities or resonators with high optical confinement. The unique van der Waals surfaces of the 2D materials enable handiness in transfer and mixing with various prefabricated photonic templates with high degrees of freedom, functionalizing as the optical gain, modulation, sensing, or plasmonic media for diverse applications. Here, we review recent advances in synergizing 2D materials to nanophotonic structures for prototyping novel functionality or performance enhancements. Challenges in scalable 2D materials preparations and transfer, as well as emerging opportunities in integrating van der Waals building blocks beyond 2D materials are also discussed.
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Affiliation(s)
- Yuan Meng
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, USA.
| | - Hongkun Zhong
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, China.
| | - Zhihao Xu
- Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Tiantian He
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, China.
| | - Justin S Kim
- Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Sangmoon Han
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, USA.
| | - Sunok Kim
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, USA.
| | - Seoungwoong Park
- Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Yijie Shen
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
- Optoelectronics Research Centre, University of Southampton, Southampton, UK
| | - Mali Gong
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, China.
| | - Qirong Xiao
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, China.
| | - Sang-Hoon Bae
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, USA.
- Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, MO, USA
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Wang R, Hu F, Meng Y, Gong M, Liu Q. High-contrast optical bistability using a subwavelength epsilon-near-zero material. OPTICS LETTERS 2023; 48:1371-1374. [PMID: 36946930 DOI: 10.1364/ol.481688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Optical bistability opens up a promising avenue toward various optical nonlinear functions analogous to their electrical counterparts, such as switches, logic gates, and memory. Free-space bistable devices have unique advantages in large-scale integration. However, most proposed free-space schemes for optical bistability have limitations in one or more aspects of low contrast ratio, compromised compatibility, slow switching speed, and bulk size. Epsilon-near-zero (ENZ) materials have recently shown an ultrafast and giant optical nonlinearity within a subwavelength scale, potentially overcoming these obstacles. Using large-mobility indium-doped cadmium oxide (CdO) as the ENZ material, we numerically demonstrate two efficient schemes for high-contrast optical bistability within a deep subwavelength size based on the ENZ mode and the Berreman mode. The ENZ wavelength can be optically tuned with a typical time scale of sub-picoseconds, giving rise to a switchable bistability between the near-zero state and the high-reflection state. Our work contributes to the advances on compact and ultrafast all-optical signal processing.
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All-optical switching in epsilon-near-zero asymmetric directional coupler. Sci Rep 2022; 12:17958. [PMID: 36289304 PMCID: PMC9606007 DOI: 10.1038/s41598-022-22573-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 10/17/2022] [Indexed: 11/30/2022] Open
Abstract
We propose an all-optical switch based on an asymmetric directional coupler structure with epsilon-near-zero (ENZ) layer. The nonlinear optical properties the of ENZ layer are analyzed by hot-electron dynamics process, and the all-optical operating performance of the switch on the silicon nitride platform is investigated. It is found that the pump-induced refractive index change in ENZ layer gives rise to a transfer of signal light in the optical system. We demonstrate that the proposed switch design features an insertion loss of < 2.7 dB, low crosstalk of < − 18.93 dB, and sub-pico-second response time at the communication wavelength of 1.55 μm. With ultrafast response, high performance, and simple structure, the device provides new possibilities for all-optical communication and signal processing.
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Jiang H, Zhao Y, Ma H, Wu Y, Chen M, Wang M, Zhang W, Peng Y, Leng Y, Cao Z, Shao J. Broad-Band Ultrafast All-Optical Switching Based on Enhanced Nonlinear Absorption in Corrugated Indium Tin Oxide Films. ACS NANO 2022; 16:12878-12888. [PMID: 35905035 DOI: 10.1021/acsnano.2c05139] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Ultrafast all-optical switches based on epsilon-near-zero (ENZ)-enhanced nonlinear refraction in transparent conducting oxides have achieved exciting results in realizing large absolute modulations. However, broad-band, polarization-independent, and wide-angle ultrafast all-optical switches have been challenging to produce, due to the inherent narrow band, polarization-dependent, and angle-dependent characteristics of the ENZ effect. To this end, we propose an ultrafast all-optical switch based on the enhanced nonlinear absorption of corrugated indium tin oxide (ITO) thin films. Taking advantage of the perfect absorption and localized field enhancement of the ENZ and localized surface plasmon resonance modes, we significantly enhanced the nonlinear absorption of the corrugated ITO film in the 1450-1650 nm telecom band. The experimental results show that the nonlinear saturable absorption coefficient of the corrugated ITO film at 1450 nm was as high as -1.5 × 105 cm GW-1, enabling all-optical switching to obtain an extinction ratio of 14.32 dB and an ultrafast switching time of 350 fs at a pump fluence of 18.51 mJ cm-2. Furthermore, the all-optical switch achieved an extinction ratio of over 15 dB and an insertion loss of approximately 2.6 dB within the 200 nm absorption band and exhibited polarization-independent and wide-angle features. The ultrafast temporal response can be attributed to intraband transient bleaching of the corrugated ITO film. Our findings demonstrate that corrugated ENZ films can overcome the inherent narrow-band, polarization-dependent, and angle-dependent problems of natural ENZ materials without increasing the response time, making them a potential ENZ ultrafast all-optical switching material platform.
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Affiliation(s)
- Hang Jiang
- Laboratory of Thin Film Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Key Laboratory of Materials for High Power Laser, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
| | - Yuanan Zhao
- Laboratory of Thin Film Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Key Laboratory of Materials for High Power Laser, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
| | - Hao Ma
- Laboratory of Thin Film Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Key Laboratory of Materials for High Power Laser, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
| | - Yi Wu
- Laboratory of Thin Film Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Key Laboratory of Materials for High Power Laser, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
| | - Meiling Chen
- Laboratory of Thin Film Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Key Laboratory of Materials for High Power Laser, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
| | - Mengxia Wang
- Laboratory of Thin Film Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Key Laboratory of Materials for High Power Laser, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
| | - Weili Zhang
- Laboratory of Thin Film Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Key Laboratory of Materials for High Power Laser, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
| | - Yujie Peng
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
| | - Yuxin Leng
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
| | - Zhaoliang Cao
- Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, People's Republic of China
| | - Jianda Shao
- Laboratory of Thin Film Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Key Laboratory of Materials for High Power Laser, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, People's Republic of China
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Hu F, Chen S, Wang R, Meng Y, Liu Q, Gong M. Tunable extreme energy transfer of terahertz waves with graphene in a nested cavity. OPTICS EXPRESS 2021; 29:34302-34313. [PMID: 34809224 DOI: 10.1364/oe.435044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/26/2021] [Indexed: 06/13/2023]
Abstract
Energy transfer is an essential light-matter interaction. The transfer efficiency is critical for various applications such as light-emitting, optical modulation, and the photoelectric effect. Two primary forms of light-matter energy transfer, including absorption and emission, can be enhanced in optical cavities. Both forms can reach an extremum inside the cavity according to the coupled-mode theory. Graphene conductivity at the terahertz frequency can be tuned from positive to negative, providing a suitable material to study switchable extremums of these two forms. We integrate graphene with a nested cavity where an infrared cavity is inserted in a terahertz cavity, thereby achieving terahertz perfect absorption at the static state and optimal gain under photoexcitation. Leveraging an inserted infrared cavity, we can elevate the working efficiency by strongly absorbing the infrared pump. We also numerically show the feasibility of electrically tunable extreme energy transfer. Our concept of the nested cavity can be extended to different materials and even to guided modes. A switchable synergy of loss and gain potentially enables high-contrast dynamic modulation and photonic devices with multiplexing functions.
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Chen Y, Kong Z, Chen F, Ding B, Zhang L, Cui S, Zhang H. Stable directional emission in active optical waveguides shielding external environmental influences. APPLIED OPTICS 2021; 60:6155-6161. [PMID: 34613280 DOI: 10.1364/ao.428559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/25/2021] [Indexed: 06/13/2023]
Abstract
The skillful confinement of light brought by the composite waveguide structure has shown great possibilities in the development of photonic devices. It has greatly expanded the application range of an on-chip system in dark-field imaging and confined the laser when containing an active medium. Here we experimentally proved a stable directional emission in an active waveguide composed of metal and photonic crystal, which is almost completely unaffected by the external environment and different from the common local light field that is seriously affected by the structure. When the refractive index of samples on the surface layer changes, it can ensure the constant emission intensity of the internal mode, while still retaining the external environmental sensitivity of the surface mode. It can also be used for imaging and sensing as a functional slide. This research of chip-based directional emission is very promising for various applications including quantitative detection of biological imaging, coupled emission intensity sensing, portable imaging equipment, and tunable micro lasers.
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Parra J, Olivares I, Ramos F, Sanchis P. Ultra-compact non-volatile Mach-Zehnder switch enabled by a high-mobility transparent conducting oxide. OPTICS LETTERS 2020; 45:1503-1506. [PMID: 32164002 DOI: 10.1364/ol.388363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 02/11/2020] [Indexed: 06/10/2023]
Abstract
Compact and broadband non-volatile silicon devices are mainly absorption based. Hence, access to low-loss non-volatile phase shifters is still a challenge. Here, this problem is addressed by using a high-mobility transparent conducting oxide such as cadmium oxide as a floating gate in a flash-like structure. This structure is integrated in a Mach-Zehnder interferometer switch. Results show an active length of only 30 µm to achieve a $ \pi $π phase shift. Furthermore, an extinction ratio of 20 dB and insertion loss as low as 1 dB may be attained. The device shows an optical broadband response and can be controlled with low-power pulses in the nanosecond range. These results open a new, to the best of our knowledge, way for enabling compact silicon-based phase shifters with non-volatile performance.
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