Optimization of diode-laser-based photoacoustic laser systems for high-sensitivity detection of water vapor methane and carbon dioxide

摘要

Abstract: Developments towards a portable sensor system for in-situ detection of low concentration of water vapor are described. The system consists of a Littman type external cavity diode laser light source operating around 1125 nm, an acoustically optimized high sensitivity measuring photoacoustic ell, a reference photoacoustic cell, home made electronics and a personal computer for measurement and system control. For high sensitivity water vapor detection a fully computerized measurement protocol has been developed. Test measurements demonstrated that the system is able to detect water vapor concentration below the 10 ppm level.!7