Application of standard and custom quartz tuning forks for quartz-enhanced photoacoustic spectroscopy gas sensing

A review on the design of quartz tuning forks and their applications in quartz-enhanced photoacoustic spectroscopy (QEPAS)-based trace gas sensors is reported. Standard commercial quartz tuning forks are used as sound wave transducers in the conventional QEPAS technique. With the development of QEPAS technology, the advent of custom quartz tuning forks has further improved the sensitivity level of QEPAS sensors. The manufacturing process of quartz tuning forks will be explained in detail in this review and the application of quartz tuning forks in QEPAS trace gas sensors in recent years will be summarized.