Optical gas sensors

In this chapter we present an overview of optical gas sensors based on sol-gel materials, with particular emphasis on surface plasmon resonance-based sensor. The definition of optical gas sensor and the main parameters used for characterizing gas sensors are described in the introduction. A section is devoted to plasmonic gas sensors which are optical sensors that use localized surface plasmons or extended surface plasmons as transducing platform. Surface plasmons are very sensitive to dielectric variations of the environment or to electron exchange and these effects have been exploited for the realization of sensitive gas sensors. Several examples of sol-gel based nanomaterials developed by our group and used as sensitive materials for optical gas sensors are presented.