Clamp-type quartz tuning fork enhanced photoacoustic spectroscopy
Qian Wu, Haohua Lv, Leqing Lin, Hongpeng Wu, Marilena Giglio, Wenguo Zhu, Yongchun Zhong, Angelo Sampaolo, Pietro Patimisco, Lei Dong, Vincenzo Spagnolo, Jianhui Yu, Huadan Zheng
Abstract
In this Letter, clamp-type quartz tuning fork enhanced photoacoustic spectroscopy (Clamp-type QEPAS) is proposed and realized through the design, realization, and testing of clamp-type quartz tuning forks (QTFs) for photoacoustic gas sensing. The clamp-type QTF provides a wavefront-shaped aperture with a diameter up to 1 mm, while keeping Q factors > 10 4 . This novel, to the best of our knowledge, design results in a more than ten times increase in the area available for laser beam focusing for the QEPAS technique with respect to a standard QTF. The wavefront-shaped clamp-type prongs effectively improve the acoustic wave coupling efficiency. The possibility to implement a micro-resonator system for clamp-type QTF is also investigated. A signal-to-noise enhancement of ∼30 times has been obtained with a single-tube acoustic micro resonator length of 8 mm, ∼20% shorter than the dual-tube micro-resonator employed in a conventional QEPAS system.