光学学报, 2006, 26 (8): 1260, 网络出版: 2007-03-15
高灵敏度离轴积分腔输出光谱技术
High-Sensitivity off-Axis Integrated Cavity Output Spectroscopy
光谱学 积分腔输出光谱技术 离轴入射 朗伯比尔定律 谱线拟合 吸收系数 spectroscopy integrated cavity output spectroscopy (ICOS) off-axis incidence Lambert-Beer's law line shape fitting absorption coefficient
摘要
利用离轴积分腔输出光谱技术,采用同时扫描激光和谐振腔腔长的方法,使用分布反馈布拉格二极管激光器探测了1.573 μm附近CO2的吸收光谱,得到很好的信噪比和灵敏度,探测灵敏度达到4×10-8 cm-1(信噪比为2,1 s积分时间)。用非线性最小二乘拟合吸收谱线方法对积分腔输出光谱已经不再适用,会造成自加宽系数变宽为实际自加宽系数的2.39倍左右,对空气加宽系数测量影响较小。为了得到正确的谱线线宽参量,应该对吸收系数进行拟合,该结论从理论和实验上得到了证明。
Abstract
Using a distributed feed back (DFB) tunable diode laser as the injection light source, absorption spectrum around 1.573 μm with high signal-to-noise ratio (SNR) and sensitivity is obtained by using off-axis integrated cavity output spectroscopy and scanning the laser and cavity simultaneously. The typical sensitivity is 4×10-8 cm-1 (SNR=2,1s integrated time). It is not valid to fit the integrated cavity output spectrum with the nonlinear least square method, and it will make the self-broadening coefficient broadened as about 2.39 times of the real value. The air-broaden coefficient approaches to the real one. Absorption coefficient fit is necessary to obtain the correct parametersof spectral line width. Theoretical analysis and experiment demonstration prove the conclusion.
赵卫雄, 高晓明, 张为俊, 黄腾. 高灵敏度离轴积分腔输出光谱技术[J]. 光学学报, 2006, 26(8): 1260. 赵卫雄, 高晓明, 张为俊, 黄腾. High-Sensitivity off-Axis Integrated Cavity Output Spectroscopy[J]. Acta Optica Sinica, 2006, 26(8): 1260.