基于可调谐半导体激光吸收光谱对CO_2浓度的测量

Measurement of Concentration of Carbon Dioxide Gas with Tunable Diode Laser Absorption Spectroscopy

CO_2作为大气中主要的温室气体,其全球变暖影响比例因素为60%,对全球生态系统和社会发展带来严重影响,因此开展CO_2的监测非常必要。基于可调谐半导体激光吸收光谱原理,在室温下通过扫描DFB激光器波长,得到CO_2位于2004 nm的直接吸收光谱,根据Beer-Lambert定律,反演出CO_2浓度。为了验证实验的精度,同时与基于非分散红外原理的生态通量的标准仪器作对比,结果显示两者的测量精确度相当,可以达到0.2 ppm。这些研究为今后的仪器小型化和外场CO_2长时间监测提供了基础。

As the main greenhouse gases in the atmosphere, CO2 takes global warming factor up to 60%, leading to a serious impact on the global ecosystem and social development. Therefore, it is necessary to carry out the monitoring of CO2. Based on the principle of tunable diode laser absorption spectroscopy（TDLAS）, a room-temperature DFB laser was used as an optical source, and an absorption line of CO2 near 2004 nm was obtained. The C02 concentration can be calculated via the Beer-Lambert law. Meanwhile, in order to prove the accuracy of the result, ecological flux standard instrument is used as the reference. The results show that both measurement accuracy is considerable, up to 0.2 ppm. The exploration of the research can provide a basis for instrument miniaturization and a long time monitoring of the CO2.