Application of diode-laser-pumped difference-frequency generation to spectroscopic trace gas detection in the atmosphere

[摘要] The application of diode-laser-pumped tunable IR sources to trace gas detection in air is discussed. The design and technology issues of CW tunable mid-infrared difference-frequency generation are addressed. Feasibility experiments are reported in which the detection of CH$sb4$, and CO was performed at low pressure and in air using two laser sources near 3.2 $mu$m, and 4.7 $mu$m, respectively. They were based on difference-frequency mixing in AgGaS$sb2$ at room temperature. Pump sources used were a diode-pumped Nd:YAG laser at 1064 nm, a laser diode at 693 nm, and a tunable fiber-coupled Ti:Sapphire laser near 795 nm, and 813 nm. Detection limits of 2.4 ppb*m/$msqrt{Hz}$ for CO, and 9.0 ppb*m/$msqrt{Hz}$ for CH$sb4$ in air are estimated for 0.1 $mu$W of IR probe power based upon the performance of the sources and detector.

[发布机构] Rice University

[效力级别] Electrical