Temporal coupled-mode theory for PT-symmetric chiral metasurfaces.
Opt Lett
; 48(21): 5503-5506, 2023 Nov 01.
Article
em En
| MEDLINE
| ID: mdl-37910688
ABSTRACT
We have developed a temporal coupled-mode theory based on quasi-normal modes to investigate the chiroptical effects in parity-time (PT) symmetric metasurfaces. The PT symmetry enforces a different constraint for the direct scattering matrix and the coupling constants, which is verified by calculating the transmission spectra originating from the chiral quasi-bound states in the continuum. What's more, the scattering matrix can be analytically continued to the complex frequency plane. We find that the zero and pole singularities of the transmission coefficients and scattering matrix play an important role in the optical chirality. The pole singularities carry a quantized topological charge of -1. Our work paves the way for studying the enhanced optical chirality in non-Hermitian metasurfaces.
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MEDLINE
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En
Ano de publicação:
2023
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Article