Long-path quartz tuning fork enhanced photothermal spectroscopy gas sensor using a high power Q-switched fiber laser.

• A long-path QEPTS gas sensor using a high power Q-switched fiber laser was proposed. • Long optical path and high power are beneficial to the QEPTS sensor. • A minimum detection limit (MDL) of 6.1 ppbv at the 48 s integration time was achieved. A long-path quartz tuning fork enhanced photothermal spectroscopy (QEPTS) gas sensor using a Q-switched fiber laser is proposed. A theoretical model is used to describe the process of the long-path QEPTS sensor and the factors that affect its performance. We can conclude that long optical path and high power are beneficial to the QEPTS sensor from the theoretical analysis. And we use our long-path QEPTS sensor for C 2 H 2 detection at the wavelength of 1531.59 nm. With the scanning time of 4 s and the peak pulse power of 127.5 mW, an Allan deviation analysis shows that our sensor has a minimum detection limit (MDL) of 6.1 ppbv at the 48 s integration time and a good linear response (R-square = 0.99796). [ABSTRACT FROM AUTHOR]