A multi-pass differential photoacoustic spectrometer at 1064 nm for ambient aerosol absorption

Jie Chen; Xianmei Qian; Wenyue Zhu; Qiang Liu; Jianjie Zheng; Tao Yang; Tengfei Yang

doi:10.1016/j.pacs.2025.100769

A multi-pass differential photoacoustic spectrometer at 1064 nm for ambient aerosol absorption

Photoacoustics. 2025 Sep 10:46:100769. doi: 10.1016/j.pacs.2025.100769. eCollection 2025 Dec.

Authors

Jie Chen¹, Xianmei Qian¹, Wenyue Zhu¹, Qiang Liu¹, Jianjie Zheng¹, Tao Yang^{1

2}, Tengfei Yang^{1

2}

Affiliations

¹ State Key Laboratory of Laser Interaction with Matter, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China.
² University of Science and Technology of China, Hefei 230026, China.

Abstract

Accurate atmospheric aerosol absorption measurements are critical for advancing our understanding of global climate effects and reginal meteorological processes. In this paper, a multi-pass differential photoacoustic spectrometer (MP-DPAS) worked at 1064 nm, was developed for the in-situ measurement of atmospheric aerosol absorption coefficients (Abs). By employing the multi-pass configuration, 22 reflections of the incident laser were achieved, thereby the photoacoustic signal was enhanced by a factor of ten. Meanwhile, the differential configuration not only suppress background noise but also amplifies the signal by a factor of two. Consequently, the MP-DPAS achieved a minimum detection limit of 0.05 Mm^-1 within an integration time of 110 s and a precision of 1.4 Mm^-1. The accuracy of the MP-DPAS was validated by comparing the measured Abs with the calculated Abs of Mie scattering theory and the variation of particle size distribution measured by SMPS (Scanning Mobility Particle Sizer).

Keywords: Absorption coefficient; Atmospheric aerosol; Multi-pass differential photoacoustic spectrometer; Photoacoustic spectroscopy.