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Journal Article
Critically Coupled Fabry-Perot Cavity with High Signal Contrast for Refractive Index Sensing
- Authors
- Gyeong Cheol Park, Kwangwook Park
- Issue Date
- 2021-10
- Citation
- Scientific Reports, v.11, pp.1-10
- ISSN
- 2045-2322
- Publisher
- Nature Research
- Language
- English
- Type
- Journal Article
- Project Code
- 21HH5900, Development of On-Time·On-Rate Wireless Access and Optical Edge Cloud Networking Technologies for High-Precision Services, Lee Joon Ki
- Abstract
- Perfect absorption at a resonance wavelength and extremely low absorption at the wavelength range of off-resonance in a one-port optical cavity is required for refractive index (RI) sensing with high signal contrast. Here, we propose and analyze an absorption-enhanced Fabry?밣erot (MAFP) cavity based on a critical coupling condition in a near-infrared wavelength range. For a one-port cavity, a thick bottom Au is used as a mirror and an absorber. To achieve the critical coupling condition, a top dielectric metasurface is employed and tailored to balance the radiation coupling and the absorption coupling rates, and the one-port cavity is theoretically analyzed using temporal coupled-mode theory. We investigate two types of MAFP structures for gas and liquid. The gas MAFP cavity shows a sensitivity of ~ 1388혻nm/RIU and a full-width at half-maximum of less than 0.7혻nm. This MAFP cavity resolves the RI change of 5 × 10?닋4 with a reflectance signal margin of 50% and achieves a signal contrast of ~ 100%. The liquid MAFP cavity shows a sensitivity of ~ 996혻nm/RIU when RI of liquid changes from 1.30 to 1.38. With tailoring the period of the metasurface maintaining its thickness, a signal contrast of ~ 100% is achieved for each specific RI range.
- KSP Keywords
- Fabry-Perot cavity, Full-width at half-maximum(FWHM), High signal, Infrared wavelengths, Near-Infrared(NIR), Off-resonance, Refractive index sensing, critical coupling, dielectric metasurface, optical cavity, perfect absorption
This work is distributed under the term of Creative Commons License (CCL)
(CC BY)
(CC BY)
