A dual-wavelength interrogation schema for trace gas photoacoustic spectroscopy
Received:September 29, 2017  Revised:November 09, 2017  download
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Author NameAffiliationE-mail
JI Yan Department of PhysicsWuhan University of Technology 15370932898@163.com 
YI Ying-Yan Wuhan University of Technology yiyingyan@163.net 
LI Min Wuhan University of Technology minli@whut.edu.cn 
Haifei Lv Wuhan University of Technology haifeilv@whut.edu.cn 
WEN Xiao-Yan Wuhan Universtiy of Technology 26988489@qq.com 
LI Yu-Lin   
Abstract:Photoacoustic spectroscopy is the most sensitive approach of trace gas analysis reaching part per trillion by volume level and available for engineering practice, but not sufficiently satisfy the measurement demand of gases with weak absorption in near infrared zone. This paper presents a simple interrogation method using a dual-wavelength schema to switch effectively between the absorption and unabsorption lines of the gas to be measured, which takes good advantage of the current modulation characteristic of laser diode. Measurement results of methane demonstrate the feasibility and a relatively simple way to reach resolution of 0.46 ppm of the dual-wavelength method when the laser power is 2.1 mW.
keywords:photoacoustic spectroscopy,dual-wavelength schema, current modulation
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Copyright:《Journal of Infrared And Millimeter Waves》