Switching of the direction of reflectionless light propagation at exceptional points in non-PT-symmetric structures using phase-change materials

Unidirectional reflectionlessness is one of the most fascinating effects at the exceptional point (EP) in a non‐Hermitian system. Herein, a polarization‐dependent non‐Hermitian radio frequency metasurface with unidirectional reflectionless (UR) phenomenon in dual frequency is proposed, which originates from the EP‐based effect. EP generation is observed in the loss‐assisted system by optimizing structure parameters. At EPs, when the incident light is x‐ or y‐polarized, ideal backward or forward reflectionlessness is spotted at 8.86 and 14.97 GHz, respectively. In contrast, the polarization state of the incident light has great influence on the UR phenomenon and controllably switches the reflected directions and frequencies. Furthermore, when the polarization angle of the incident light is 50°, bilateral unidirectional reflectionlessness can be observed at two characteristic frequencies. The study on the non‐Hermitian metasurface provides experimental solutions toward EP‐based effects, which are greatly beneficial to the development of unidirectional devices.

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“…Therefore, the EP‐based UR effect has great application potential in optical filters and optical diode‐like devices. [ 41 ]…”

Section: Resultsmentioning

confidence: 99%

Experimental Demonstration of the Non‐Hermitian Radio Frequency Metasurface with Polarization‐Dependent Unidirectional Reflectionless Propagation

Gao

Yuan

Sun

et al. 2022

Advanced Photonics Research

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“…This peculiarity makes them interesting for ultra-sensitive sensor devices, single-mode lasers and quantum optics [282]. The use of PCMs provides a fruitful approach to precise tailoring material loss in space and time and hence can facilitate the designing and realization of structures supporting EPs [287] especially in the integrated on-chip scenario.…”

Section: Perspective and Outlookmentioning

confidence: 99%

Tunable nanophotonics enabled by chalcogenide phase-change materials

et al. 2020

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AbstractNanophotonics has garnered intensive attention due to its unique capabilities in molding the flow of light in the subwavelength regime. Metasurfaces (MSs) and photonic integrated circuits (PICs) enable the realization of mass-producible, cost-effective, and efficient flat optical components for imaging, sensing, and communications. In order to enable nanophotonics with multipurpose functionalities, chalcogenide phase-change materials (PCMs) have been introduced as a promising platform for tunable and reconfigurable nanophotonic frameworks. Integration of non-volatile chalcogenide PCMs with unique properties such as drastic optical contrasts, fast switching speeds, and long-term stability grants substantial reconfiguration to the more conventional static nanophotonic platforms. In this review, we discuss state-of-the-art developments as well as emerging trends in tunable MSs and PICs using chalcogenide PCMs. We outline the unique material properties, structural transformation, and thermo-optic effects of well-established classes of chalcogenide PCMs. The emerging deep learning-based approaches for the optimization of reconfigurable MSs and the analysis of light-matter interactions are also discussed. The review is concluded by discussing existing challenges in the realization of adjustable nanophotonics and a perspective on the possible developments in this promising area.

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“…This peculiarity makes them interesting for ultra-sensitive sensor devices, single-mode lasers and quantum optics [254]. The use of PCMs provides a fruitful approach to precise tailoring material loss in space and time and hence can facilitate the designing and realization of structures supporting EPs [259] especially in the integrated on-chip scenario.…”

Section: Perspective and Outlookmentioning

confidence: 99%

Tunable nanophotonics enabled by chalcogenide phase-change materials

Abdollahramezani,

Hemmatyar,

Taghinejad

et al. 2020

Preprint

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Nanophotonics has garnered intensive attention due to its unique capabilities in molding the flow of light in the subwavelength regime. Metasurfaces (MSs) and photonic integrated circuits (PICs) enable the realization of mass-producible, cost-effective, and highly efficient flat optical components for imaging, sensing, and communications. In order to enable nanophotonics with multi-purpose functionalities, chalcogenide phase-change materials (PCMs) have been introduced as a promising platform for tunable and reconfigurable nanophotonic frameworks. Integration of non-volatile chalcogenide PCMs with unique properties such as drastic optical contrasts, fast switching speeds, and long-term stability grants substantial reconfiguration to the more conventional static nanophotonic platforms. In this review, we discuss state-of-the-art developments as well as emerging trends in tunable MSs and PICs using chalcogenide PCMs. We outline the unique material properties, structural transformation, electro-optic, and thermo-optic effects of well-established classes of chalcogenide PCMs. The emerging deep learning-based approaches for the optimization of reconfigurable MSs and the analysis of light-matter interactions are also discussed. The review is concluded by discussing existing challenges in the realization of adjustable nanophotonics and a perspective on the possible developments in this promising area.

show abstract

Switching of the direction of reflectionless light propagation at exceptional points in non-PT-symmetric structures using phase-change materials

Cited by 29 publications

References 67 publications

Experimental Demonstration of the Non‐Hermitian Radio Frequency Metasurface with Polarization‐Dependent Unidirectional Reflectionless Propagation

Experimental Demonstration of the Non‐Hermitian Radio Frequency Metasurface with Polarization‐Dependent Unidirectional Reflectionless Propagation

Tunable nanophotonics enabled by chalcogenide phase-change materials

Tunable nanophotonics enabled by chalcogenide phase-change materials

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