Abstract

Photoacoustic spectroscopy, based on an external cavity diode laser operating at 1431 nm, was used for measuring CO₂ concentration as a minority component in a gas mixture. By using N₂ as a buffer gas, a molecular relaxation effect was observed, which influenced both the amplitude and the phase of the measured photoacoustic signal and consequently reduced the sensitivity of the PA system. This molecular relaxation effect could be suppressed by adding water vapor of a constant and relatively high (~4%) concentration to the gas sample. In parallel with this, the arising spectral interference between H₂O and CO₂ necessitated the development of a simple yet efficient signal analysis method, which increased the sensitivity of the system by more than one order of magnitude and accordingly reduced the minimum detectable CO₂ concentration down to ~1000 ppm.

Simultaneous detection of greenhouse gases CH₄ and CO₂ based on a dual differential photoacoustic spectroscopy system

Fupeng Wang, Jinghua Wu, Yaopeng Cheng, Liyan Fu, Jianguo Zhang, and Qiang Wang
Opt. Express 31(21) 33898-33913 (2023)

Noise-immune cavity-enhanced optical heterodyne molecular spectrometry on N₂O 1.283  μm transition based on a quantum-dot external-cavity diode laser

Tzu-Ling Chen and Yi-Wei Liu
Opt. Lett. 40(18) 4352-4355 (2015)

High sensitive detection of nitric oxide using laser induced photoacoustic spectroscopy at 213 nm

Mohammed A. Gondal, Ahmed Asaad I. Khalil, and Noura Al-Suliman
Appl. Opt. 51(23) 5724-5734 (2012)

Diode laser-based photoacoustic spectroscopy with interferometrically-enhanced cantilever detection

Toni Laurila, Heidi Cattaneo, Vesa Koskinen, Jyrki Kauppinen, and Rolf Hernberg
Opt. Express 13(7) 2453-2458 (2005)

Highly sensitive acetylene detection based on multi-pass retro-reflection-cavity-enhanced photoacoustic spectroscopy and a fiber amplified diode laser

Yufei Ma, Shunda Qiao, Ying He, Yu Li, Zhonghua Zhang, Xin Yu, and Frank K. Tittel
Opt. Express 27(10) 14163-14172 (2019)