Cascaded PT-symmetric artificial sheets: multimodal manipulation of self-dual emitter-absorber singularities, and unidirectional and bidirectional reflectionless transparencies
Cascaded PT-symmetric artificial sheets: multimodal manipulation of self-dual emitter-absorber singularities, and unidirectional and bidirectional reflectionless transparencies
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DOI：
10.1088/1361-6463/ac3300
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发表时间：
2021-10
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影响因子：
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通讯作者：
Minye Yang;Zhilu Ye;M. Farhat;Pai-Yen Chen
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作者：
Minye Yang;Zhilu Ye;M. Farhat;Pai-Yen Chen
我们引入级联奇偶时间（PT）对称的人工片（例如超表面或频率选择表面），可以表现出多个高阶激光吸收模式和双向无反射传输谐振内的PT-破相，以及单向无反射传输谐振与例外点（EP）。我们推导出获得这些模式所需的增益-损耗参数及其有趣的物理性质的显式表达式。利用级联的PT结构，可以显著降低自对偶激光吸收器工作的增益-损耗阈值，而EP保持不变。我们进一步研究了基于这种多模态激光吸收体的干涉传感，并证明其灵敏度可能非常高，并且与沿光传播方向沿着的超表面的数量成比例。
We 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 may be exceptionally high and proportional to the number of metasurfaces along the light propagation direction.