Dual-guiding-layer resonance structure with an embedded metasurface for quasi-critical coupling without a perfect mirror

Autor: Gyeong Cheol Park, Kwangwook Park
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Scientific Reports, Vol 10, Iss 1, Pp 1-10 (2020)
Scientific Reports
Park, G C & Park, K 2020, ' Dual-guiding-layer resonance structure with an embedded metasurface for quasi-critical coupling without a perfect mirror ', Scientific Reports, vol. 10, no. 1, 16014 . https://doi.org/10.1038/s41598-020-72983-8
ISSN: 2045-2322
Popis: We propose an all-dielectric quasi-one-port resonance structure that achieves near perfect absorption without the use of a back mirror. The structure mainly consists of a high-refractive-index silicon metasurface and surrounding high-refractive-index guiding layers. The dual-guiding-layer (DGL) structure has high background reflectance and is designed to have a ratio of two decay rates into the upper and lower regions within a wider range. When an absorbing material is introduced into a DGL system, it can be designed to achieve a near critical-coupling condition by reducing the constraints in the two decay rates. By using single-layer graphene as an absorbing material, the DGL resonance structure shows an absorption of ~ 97% and a phase change of ∼ 0.95π near the wavelength of 1550 nm, confirming quasi-critical coupling. The optimized DGL structure is relatively insensitive to potential fabrication imperfections, and consequently, the expected average peak wavelength and absorption are obtained as 1549.29 nm and 96.74%, respectively. Angle-dependent absorption confirms that maximum absorption occurs under normal incidence. The DGL absorber is also designed to cover the whole C-band region, in order to meet the quasi-critical-coupling condition. All mode profiles are similarly quasi-symmetric along the metasurface due to the same DGL resonance mechanism.
Databáze: OpenAIRE
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