Quartz-enhanced photoacoustic spectroscopy employing a Vernier-effect distributed feedback-quantum cascade laser for multiple analytes detection

Here we report on the multi-gas detection of carbon monoxide (CO), nitrous oxide (N₂O), carbon dioxide (CO₂), and water vapor (H₂O) by using a quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor exploiting a Vernier effect-based quantum cascade laser as excitation source. The device emission wavelengths ranged from 2100 cm^-1 to 2250 cm^-1. The achieved minimum detection limits were 6 ppb, 7 ppb, and 71 ppm fr CO, N₂O, and CO₂, respectively, at 100 ms of integration time. Finally, QEPAS sensor performances were tested retrieving the concentrations of the target gases within laboratory air.