Low power consumption quartz-enhanced photoacoustic gas sensor employing a quantum cascade laser in pulsed operation
We report here an analysis of the performance of a quartz-enhanced photoacoustic (QEPAS) system operating in a pulsed mode by employing a quantum cascade laser (QCL). The QEPAS system is based on a quartz tuning fork (QTF) having fundamental resonance frequency of 4.2 kHz and a first overtone resonance of 25.4 KHz. Water vapor was used as a target gas by selecting its absorption line falling at 1296.5 cm-1 with a line strength of 1.69⋅10-22 cm/molecule. The QEPAS signal was investigated, while varying the QCL duty-cycle from continuous wave operation, down to 5%, which corresponds to a laser power consumption of 0.17 mW and a pulse-width of 4 μs.
quartz tuning fork; photoacoustic spectroscopy; quantum cascade laser; gas sensing