Novel Gas Sensor Based on Difference Frequency Mixing Using All Fibre Beam Delivery

Abstract

Tunable infrared laser absorption spectroscopy has proven to be a powerful technique for accurately determining the real time concentrations of trace pollutants in both point monitoring and open path configurations (1). For the detection of molecules including many of the common pollutants, and most of the hydrocarbons, the key spectral region for absorption spectroscopy is in the mid-infrared (3-5 μm).