Evanescent-field laser sensor for in-situ monitoring of volcano gas emissions

Abstract

A DFB laser diode (1.57 µm) is guided through a pure core fused silica fiber. Tuning the laser frequency across molecular resonances will change the frustrated (FTR) and the attenuated total reflection (ATR). Such an evanescent-field laser sensor is used for in-situ monitoring of H2S in volcano gases at the site “Solfatara”(Italy).