光谱学与光谱分析, 2012, 32 (1): 41, 网络出版: 2012-02-20
利用离轴腔增强吸收光谱技术探测实际大气中的二氧化碳
Off-Axis Cavity Enhanced Absorption Spectroscopy Detection Techniques for the Measurement of Carbon Dioxide
离轴腔增强吸收光谱 高精密度光学谐振腔 最小可探测浓度 波长调制 Off-axis cavity enhanced absorption spectroscopy CO2 CO2 High-finesse optical resonant cavity Minimum detectable concentration Wavelength modulation
摘要
以1.573 μm窄线宽可调谐半导体激光器作光源, 结合高精细度光学谐振腔的离轴腔增强吸收光谱技术, 选择CO2在6 357.311 6 cm-1的吸收谱线, 对实际大气CO2分子进行了测量。 为了得到更准确的有效方程, 对谐振腔吸收程长的标定方法进行了研究, 给出了一种简单、 实用的标定方法。 实验结果表明, 高精密度光学谐振腔的有效吸收程长为~1 195.73 m, 测得实际大气CO2的浓度为~388.3 ppm(S/N≈22), 最小可探测浓度为17.65 ppm。 将波长调制技术与OA-CEAS技术结合后, 最终将CO2分子的最小可探测浓度提高到0.36 ppm(S/N≈1 064)。
Abstract
The spectrum of carbon monoxide was obtained around 1.573 μm using a tunable distributed feedback semiconductor laser with a high-finesse cavity at room temperature via off-axis cavity enhanced absorption (CEA) spectroscopic technique. The absorption line of carbon monoxide at 6 357.311 6 cm-1 was chosen for trace detection. Meanwhile, in order to get more accurate measurements, absorption path length of the cavity calibration methods was studied, and a simple and practical calibration method was given. The results show that, the equivalent absorption path length of high-precision optical resonator was ~1 195.73 m. At last, we got the concentration of carbon monoxide in the real atmosphere to be ~388.346 ppm (S/N≈22), and the detection limit of carbon monoxide was 17.65 ppm. By combination of wavelength modulation technology and OA-CEAS technology, a minimum detectable concentration of 0.36 ppm (S/N≈1 064) was achieved eventually.
赵辉, 王贵师, 蔡廷栋, 高晓明. 利用离轴腔增强吸收光谱技术探测实际大气中的二氧化碳[J]. 光谱学与光谱分析, 2012, 32(1): 41. ZHAO Hui, WANG Gui-shi, CAI Ting-dong, GAO Xiao-ming. Off-Axis Cavity Enhanced Absorption Spectroscopy Detection Techniques for the Measurement of Carbon Dioxide[J]. Spectroscopy and Spectral Analysis, 2012, 32(1): 41.