We proposed a refractive index sensor using a phase-compensated cavity whose resonant wavelength can be tuned by the alignment between layers. The structures are composed of double-layered nanoslit array, which has total thickness of 100 nm while the cavity length is 30 nm thick. Using nanoslit array as a reflector has made it possible to design the phase shift carefully so that the subwavelength Fabry-Pérot cavity can be obtained. When the cavity is filled with sensing medium, where the field enhancement is achieved by Fabry-Pérot (FP) resonance, the proposed structure is found to achieve sensitivity ranging from 337 nm/RIU to 1250 nm/RIU at each different alignment. The resonant wavelength ranges from 1100 nm to 2500 nm, which contains biological windows and telecommunication wavelength range, so the structure is expected to be used in various purposes.

Date Published: 23 April 2017
PDF: 4 pages
Proc. SPIE 10323, 25th International Conference on Optical Fiber Sensors, 1032351 (23 April 2017); doi: 10.1117/12.2266807

Published in SPIE Proceedings Vol. 10323:
25th International Conference on Optical Fiber Sensors
Youngjoo Chung; Wei Jin; Byoungho Lee; John Canning; Kentaro Nakamura; Libo Yuan, Editor(s)