Dual-spectroscopy technique based on quartz crystal tuning fork detector

[Display omitted] •Quartz crystal tuning forks (QCTFs) as valuable components have been widely used for developing sensitive sensors.•Broadband tunable ECQCL and QCTF based dual-spectroscopy technique was firstly proposed for gas detection.•Comparing to the popular QEPAS technique, a sensitivity enhancement of 4–7 times was obtained for the proposed dual-spectroscopy technique. Quartz crystal tuning fork (QCTF) as a sensitive element and valuable component has been widely used for developing mass and stress sensor, pressure and temperature sensor, optoacoustic transducer and photoelectric detector, due to its high quality factor, high stability and precision, and low power consumption. In this paper, QCTF was reported for simultaneous detection of both acoustic signal induced by photoacoustic effect (i.e. photoacoustic spectroscopy) and light signal from molecular absorption process (i.e. direct absorption spectroscopy). A broadband tunable external cavity quantum cascade laser (ECQCL) and two QCTFs with same resonant frequency was demonstrated for dual-spectroscopy technique detection of gas concentration. The results indicated that the proposed dual-spectroscopy technique can be efficiently utilized to enhance sensitivity of QCTF based gas sensors. Comparing to the common QEPAS technique, a sensitivity enhancement of 4–7 times was obtained for the proposed dual-spectroscopy technique.