激光技术2012，Vol.36Issue(3)：390-393,397,5.DOI:10.3969/j.issn.1001-3806.2012.03.027
波长调制光谱检测下限计算方法的研究
Study on calculation method of detection limit based on wavelength modulation spectroscopy
蔡彦 1吴尚谦 1伍昂 1翟维 1董跃辉1
作者信息
摘要
Abstract
In the study of calculation method of atmospheric trace gas detection limit based on wavelength modulation spectroscopy, it is extremely important to describe the magnitude of the absorption signal and noise objectively and accurately. In order to study the effect of residual amplitude modulation noise on the detection limit when the wavelength of a semiconductor diode laser is modulated directly, the second harmonic signal analysis and extraction method were used in theoretical derivation taking into account the frequency modulation and amplitude modulation simultaneously. The difference value between the peak and valley of the second harmonic signal was utilized as detection signal. The signal-to-noise ratio (SNR) and detection limit of the tunable diode laser absorption spectroscopy detection system were theoretically analyzed. Under the condition of Lorentzian absorption lineshape, accurate calculation data of the impact of the residual amplitude modulation noise on the SNR and the detection limit were obtained. The results show that the residual amplitude modulation noise is an important factor affecting the detection limit under the condition of large absorption linewidth.关键词
光谱学/检测下限/波长调制光谱/信噪比/残余振幅调制Key words
spectroscopy/ detection limit/ wavelength modulation spectroscopy/ signal-to-noise ratio/ residual amplitude modulation分类
数理科学引用本文复制引用
蔡彦,吴尚谦,伍昂,翟维,董跃辉..波长调制光谱检测下限计算方法的研究[J].激光技术,2012,36(3):390-393,397,5.
