SPR chromatic sensor with colorimetric registration for detection of gas molecules

In this work, we have proposed and tested a new version of an optoelectronic sensor for detecting gas molecules based on the effect of spectral surface plasmon resonance (SPR) in the chromatic mode with colorimetric registration of the R, G, B color components of reflected light. A thin 40-nm silver film on the base face of the prism with SPR excitation in the Kretschmann geometry is used as an optical sensitive element that allows us to realize a full-fledged SPR effect in the entire visible range of the spectrum from 450 to 700 nm. The physical nature of the sensory effect is a change in the refractive index of the sensitive coating on the silver film, which directly affects the SPR parameters. The films of polyvinyl formal ethylal were used as a coating selective to the number of organic analytes. A laboratory version of the portable device for implementation of a gas sensor based on the SPR-RGB effect was created. Performance of the proposed sensory method and the corresponding device were assessed using different types of alcohols as volatile organic analytes.