Chinese Optics Letters, 2007, 5 (9): 552, Published Online: Sep. 11, 2007
Behaviors of harmonic signals in wavelength-modulated spectroscopy under high absorption strength Download: 774次
波长调制光谱 谐波信号 高吸收强度 300.1030 Absorption 300.6340 Spectroscopy, infrared 300.6260 Spectroscopy, diode lasers 300.6380 Spectroscopy, modulation
Abstract
Behaviors of harmonic signals in wavelength modulation spectroscopy (WMS) for gas detection with Lorentzian line under high absorption strength are investigated. Approximate analytic expressions of the second, fourth, and sixth harmonics on the strength are presented in concise forms. Simulations show that the expressions are in agreement with the Fourier expansion by numerical integration. It is expected theoretically and experimentally in a WMS system for methane detection that there are not only a maximum, but also a null point in the harmonics versus strength relations, which should be of practical importance in methane sensing applications.
Yuntao Wang, Haiwen Cai, Jianxin Geng, Zhengqing Pan, Dijun Chen, Zujie Fang. Behaviors of harmonic signals in wavelength-modulated spectroscopy under high absorption strength[J]. Chinese Optics Letters, 2007, 5(9): 552.