For highly sensitive and selective photoacoustic (PA) trace-gas sensing it is desirable to use high power light sources with large wavelength tunability in the mid-infrared (MIR) region, where most molecules have strong vibrational transitions. The OPO technology is an old technology, but still an excellent choice as light source for PA spectroscopy. The advantages are their molecular specificity due to large wavelength tunability (1.5 to 5µm), high energy output, cost-effectiveness and compactness . The tunability of OPOs together with PA allow for multi-gas detection of several components with common signal processing and data analysis. MIR OPOs can operate in different configurations both pulsed and continuous wave (CW). The pulsed operation results in high peak power, potentially nonlinear absorption effects and a normalized noise equivalent absorption that is not extreme. We demonstrate a novel miniaturized PA trace gas analyzer platform integrated with a MIR OPO targeting the major market opportunity of environmental monitoring and breath analysis [2,3].
© 2019 IEEEPDF Article