Ultrasensitive plasmonic sensing in air using optical fibre spectral combs.
Surface plasmon polaritons (SPP) can be excited on metal-coated optical fibres, enabling the accurate monitoring of refractive index changes. Configurations reported so far mainly operate in liquids but not in air because of a mismatch between permittivities of guided light modes and the surrounding medium. Here we demonstrate a plasmonic optical fibre platform that overcomes this limitation. The underpinning of our work is a grating architecture-a gold-coated highly tilted Bragg grating-that excites a spectral comb of narrowband-cladding modes with effective indices near 1.0 and below. Using conventional spectral interrogation, we measure shifts of the SPP-matched resonances in response to static atmospheric pressure changes. A dynamic experiment conducted using a laser lined-up with an SPP-matched resonance demonstrates the ability to detect an acoustic wave with a resolution of 10-8refractive index unit (RIU). We believe that this configuration opens research directions for highly sensitive plasmonic sensing in gas.
Department of Electromagnetism and Telecommunication, University of Mons, Boulevard Dolez 31, 7000 Mons, Belgium.
Christophe
C
Caucheteur
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, 601 Huangpu Avenue West, Guangzhou 510632, China.
Tuan
0000-0001-6189-1335
T
Guo
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, 601 Huangpu Avenue West, Guangzhou 510632, China.
Fu
F
Liu
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, 601 Huangpu Avenue West, Guangzhou 510632, China.
Bai-Ou
BO
Guan
Department of Electronics, Carleton University, 1125 Colonel By Drive, Otrawa K1S 5B6, Canada.
Jacques
0000-0002-4177-928X
J
Albert