Quasi-bound states in the continuum empowering a transmissive terahertz narrowband filter with high Q and a broad sideband free of interferential distortion.
Opt Lett
; 49(10): 2753-2756, 2024 May 15.
Article
en En
| MEDLINE
| ID: mdl-38748153
ABSTRACT
Most currently available terahertz (THz) narrowband filters contain a metal and a substrate, which introduce absorption loss and spectral fluctuations caused by a Fabry-Perot interference in substrates. To address these issues, we employ quasi-bound states in the continuum (BICs) for the design and realization of a substrate-free all-dielectric THz transmissive narrowband filter. Under oblique incidence, the symmetry-protected BICs break and collapse into high-Q transmissive quasi-BIC modes, thereby achieving narrowband filtering. The filter not only minimizes energy loss but also demonstrates a smooth filtering response without an interferential spectral fluctuation associated with the substrate. An experimental high Q value of â¼127 at 4.1â
THz with a broad sideband of â¼1.5â
THz with transmittance below 10% is achieved.
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MEDLINE
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En
Revista:
Opt Lett
Año:
2024
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Article
Pais de publicación:
Estados Unidos