Fiber optic coupled surface plasmon resonance sensor based Ag-TiO2 films for hydrogen detection

• Optic fiber coupled surface plasmon resonance senso is proposed for hydrogen sensing. • The optical double-path SPR design is simple, stable and takes advantage of intensity interrogation. • An Ag/TiO 2 film deposited on the prism substrate can be replaced for various sensing applications. We propose and demonstrate the fiber optic Surface Plasmon Resonance (SPR) for hydrogen sensing based on Ag/TiO 2 at the telecommunications wavelength of 1550 nm . The sensor using TiO 2 as a sensitive layer for hydrogen detection consists of a multilayer film of 45 nm Ag/110 nm TiO 2 deposited on the coupling prism substrate. An intensity interrogation SPR with Kretschmann configuration is designed, where SPR phenomenon will occur at the interface of the Ag/TiO 2 film, and the hydrogen concentration will be detected by measuring the change in the reflected intensity. The sensitivity of the sensor is optimal at an Ag/TiO 2 thickness. Simulation and experimental results demonstrate that the fiber-optic SPR sensor developed provides hydrogen sensing and has a high sensitivity to a hydrogen concentration ranging between 14.7% and 25% Hydrogen in Air, reaching 523nW/%.