Trace gas sensing based on single-quartz-enhanced photoacoustic-photothermal dual spectroscopy.

A single-quartz-enhanced dual spectroscopy (S-QEDS)-based trace gas sensor is reported for the first time, to the best of our knowledge. In S-QEDS, a quartz tuning fork (QTF) was utilized to detect the photoacoustic and photothermal signals simultaneously and added the two signals together. The S-QEDS technique not only improved the detection performance but also avoided the issue of resonant frequency mismatching of QTFs for the multi-QTFs-based sensor systems. Water vapor (${\rm H}_2{\rm O}$) was selected as the target gas to investigate the S-QEDS sensor performance. The photoacoustic, photothermal, and composited signals were measured, respectively, under the same conditions. The experimental results verified the ideal adding of the photoacoustic and photothermal signals by using a single QTF in this S-QEDS sensor system.