Quartz-enhanced photoacoustic spectroscopy employing pilot line manufactured custom tuning forks

Huadan Zheng; Yihua Liu; Haoyang Lin; Bin Liu; Xiaohang Gu; Dongquan Li; Bincheng Huang; Yichao Wu; Linpeng Dong; Wenguo Zhu; Jieyuan Tang; Heyuan Guan; Huihui Lu; Yongchun Zhong; Junbin Fang; Yunhan Luo; Jun Zhang; Jianhui Yu; Zhe Chen; Frank K Tittel

doi:10.1016/j.pacs.2019.100158

Quartz-enhanced photoacoustic spectroscopy employing pilot line manufactured custom tuning forks

Photoacoustics. 2019 Dec 26:17:100158. doi: 10.1016/j.pacs.2019.100158. eCollection 2020 Mar.

Authors

Huadan Zheng^{1

2

3}, Yihua Liu², Haoyang Lin², Bin Liu⁴, Xiaohang Gu², Dongquan Li², Bincheng Huang², Yichao Wu⁵, Linpeng Dong^{1

2}, Wenguo Zhu^{1

2}, Jieyuan Tang¹, Heyuan Guan¹, Huihui Lu¹, Yongchun Zhong¹, Junbin Fang³, Yunhan Luo¹, Jun Zhang¹, Jianhui Yu^{1

2

3}, Zhe Chen^{1

2

3}, Frank K Tittel⁶

Affiliations

¹ Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Jinan University, Guangzhou, 510632, China.
² Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes, Department of Optoelectronic Engineering, Jinan University, Guangzhou, 510632, China.
³ Guangdong Provincial Engineering Technology Research Center on Visible Light Communication and the Guangzhou Municipal Key Laboratory of Engineering Technology on Visible Light Communication, Jinan University, Guangzhou, 510632, China.
⁴ School of Physics and Optoelectronic Engineering, Foshan University, Foshan, 528000, China.
⁵ Department of Electrical and Computer Engineering, University of Washington, Seattle, Washington 98195, USA.
⁶ Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA.

Abstract

Pilot line manufactured custom quartz tuning forks (QTFs) with a resonance frequency of 28 kHz and a Q value of >30, 000 in a vacuum and ∼ 7500 in the air, were designed and produced for trace gas sensing based on quartz enhanced photoacoustic spectroscopy (QEPAS). The pilot line was able to produce hundreds of low-frequency custom QTFs with small frequency shift < 10 ppm, benefiting the detecting of molecules with slow vibrational-translational (V-T) relaxation rates. An Au film with a thickness of 600 nm were deposited on both sides of QTF to enhance the piezoelectric charge collection efficiency and reduce the environmental electromagnetic noise. The laser focus position and modulation depth were optimized. With an integration time of 84 s, a normalized noise equivalent absorption (NNEA) coefficient of 1.7 × 10^-8 cm^-1∙W∙Hz^-1/2 was achieved which is ∼10 times higher than a commercially available QTF with a resonance frequency of 32 kHz.

Keywords: Gas sensing; Photoacoustic detection; Photoacoustic spectroscopy; Quartz tuning fork.