Surface plasmon resonance features of corrugated gold films: wavelength interrogation mode for exhaled gas detection

The characterization of a surface plasmon resonance sensor operating in the grating mode has been explored theoretically and experimentally. Wavelength interrogation mode was exploited at specular reflection in the gas phase for thin gold films, deposited onto a corrugated polymer substrate by sputtering. Some tests using water vapor were performed and the achievable responsivity at specular reflection was determined experimentally to be 87 nm/RIU and the limit of detection of 13.2×10−3 RIU was calculated. The good agreement between experimental and theoretical results confirms the correctness of the methodology and the feasibility of the proposed sensing system.