High Sensitivity Isotopic Gas Concentration-Ratio Measurement using Isotopic Gas Laser Oscillation

为了高灵敏度测量微量气体混合物的同位素浓度比，特别是二氧化碳同位素，我们测试了一个含有腔内吸收电池的^<12>CO_2-^<13>CO_2复合激光系统。从理论上考察了腔内吸收池配置可获得的灵敏度提高，发现灵敏度提高约为100。为了估计该系统的最终灵敏度，我们尝试检测大气和人工呼吸中的^<13>CO_2和^<12>CO_2。采用腔内吸收腔的^<13>CO_2激光器对大气和人工环境中的CO_2进行了检测，本系统的最低检测浓度估计为20ppb。

For high sensitivity measurement of isotopic concentration-ratio of trace-level gas mixture, particularly including carbon dioxide isotopes, we tested a ^<12>CO_2-^<13>CO_2 composite laser system containing intracavity absorption cells. Sensitivity enhancement obtainable by the intracavity absorption cell configuration was examined theoretically and found to be around 100.To estimate the ultimate sensitivity of the present system, we tried to detect ^<13>CO_2 and ^<12>CO_2 in atmospheric air and artificial breath.^<13>CO_2 inclouded in atmospheric air and in the artificial were detected by a ^<13>CO_2 laser having the intracavity absorption cell, minimum detectable concentration by the present system was estimated to be 20ppb.