Abstract
We herein introduce cascaded parity-time (PT)-symmetric artificial sheets (e.g., metasurfaces or frequency selective surfaces) that may exhibit multiple higher-order laser-absorber modes and bidirectional reflectionless transmission resonances within the PT-broken phase, as well as a unidirectional reflectionless transmission resonance associated with the exceptional point (EP). We derive the explicit expressions of the gain-loss parameter required for obtaining these modes and their intriguing physical properties. By exploiting the cascaded PT structures, the gain-loss threshold for the self-dual laser-absorber operation can be remarkably lowered, while the EP remains unaltered. We further study interferometric sensing based on such a multimodal laser-absorber and demonstrate that its sensitivity could be unprecedentedly high and proportional to the number of metasurfaces along the light propagation direction.
Original language | English (US) |
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Journal | Journal of Physics D: Applied Physics |
DOIs | |
State | Published - Oct 25 2021 |
Bibliographical note
KAUST Repository Item: Exported on 2021-10-29Acknowledgements: PYC would like to thank NSF ECCS-1917678 Grant for supporting this work.
ASJC Scopus subject areas
- Surfaces, Coatings and Films
- Acoustics and Ultrasonics
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics