二氧化碳(Carbon Dioxide，CO2)是一种关键的温室气体，对地球气候和生态系统调节有重要作用，准确检测痕量CO2浓度对评价温室效应意义重大。一般情况下，气体分子在中红外光谱范围存在强吸收，可以实现高灵敏探测，因此，以4。219 μm中红外波段的带间级联激光器为光源结合可调谐半导体激光吸收光谱技术(Tunable Diode Laser Absorp-tion Spectroscopy，TDLAS)设计了小型化CO2 监测仪器。在不同标气浓度下对仪器进行了标定，并通过分析Allan方差，得出积分时间在8。7 s时对应的最低检测限为16。6×10-9，满足温室效应研究对 CO2 气体的高灵敏测量需求。采用仪器对大气 CO2 连续监测8天，并与商用仪器LGR进行对比，充分验证了小型化CO2监测仪器的可靠性，以及中红外光源与TDLAS技术相结合的气体浓度检测方法在大气CO2准确测量方面的可行性。该系统具有结构简单、体积小、功耗低和质量轻的特点，为建设空基无人机平台的CO2监测能力提供了技术支持。
Mid-infrared laser absorption spectroscopy CO2 spectrometer
Carbon Dioxide(CO2),as the most crucial greenhouse gas,significantly influences the regula-tion of Earth's climate and ecosystems.Accurately detecting trace CO2 concentrations is vital for assessing the greenhouse effect.Gas molecules exhibit strong absorption in the mid-infrared range,which is advanta-geous for highly sensitive trace gas detection.This paper describes the design of a compact CO2 monitoring instrument using an interband cascade laser(ICL)at 4.219 μm as the light source,paired with Tunable Di-ode Laser Absorption Spectroscopy(TDLAS).The instrument was calibrated with various standard gas concentrations and,using Allan variance analysis,achieved a detection limit of 16.6×10-9 with an integra-tion time of 8.7 s,meeting the requirements for sensitive CO2 measurements in atmospheric monitoring.Additionally,the instrument was employed to monitor atmospheric CO2 over eight consecutive days and was benchmarked against the commercial LGR instrument,confirming the reliability of our miniaturized CO2 monitor and the effectiveness of combining mid-infrared light source with TDLAS technology for pre-cise atmospheric CO2 measurement.The findings offer a technical reference for high-precision CO2 concen-tration detection,while the system's simple structure,compact size,low power consumption,and light-weight design are ideal for developing CO2 monitoring capabilities on airborne platforms.
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