差分吸收激光雷达是探测大气CO₂时间和空间分布不可或缺的工具。2.0 μm波段Ho:Tm:YLF或Ho:Tm:LuLiF激光器复合外差接收机，1.6 μm种子注入的KTP光参量振荡器或参量发生器复合光电倍增管的光子计数技术，可以探测7 km以下对流层大气CO₂混合比的分布。调制连续波种子激光强度、共用1.6 μm光纤放大器，以及相关检测技术的使用，积分路径差分吸收激光雷达在大气CO₂柱浓度探测方面具有独特的优点和特色。探测大气二氧化碳柱浓度的空间计划有美国NASA的ASENDS计划，采用脉冲式、积分路径差分吸收工作方式。用CO₂气体吸收池作为参照物,稳定种子光频率和精确控制谐振腔长，锁定发射机的on光源波长，是差分吸收激光雷达探测大气二氧化碳的关键技术。

Differential absorption lidar is an indispensable tool to measure atmospheric CO₂ for temporal and spatial distribution. The 2.0 μm wavelength Ho:Tm:YLF/Ho:Tm:LuLiF lidar were used for remote sensing atmospheric CO₂ with heterodyne receiver. The KTP parametric oscillator was injected into the seeds, and a differential absorption lidar (DIAL) system of 1.6 μm by using the photon counting technique to profile the atmospheric CO₂ in the troposphere under 7 km. Modulation continuous wave seed laser intensity and the integral path differential absorption lidar, common 1.6 μm optical fiber amplifier, and the use of correlation detection technique, have unique advantages and characteristics in the detection of atmospheric CO₂ column concentrations. The space program for detecting atmospheric CO₂ column concentrations is NASA's ASENDS (active sensing of CO₂ emission over nights, days, and seasons) mission which adopts the method of pulse and integral path differential absorption. The absorption of CO₂ gas cell as a reference to stabilize seed light frequency and the precise control of cavity length lock the on-line wavelength of transmitter, is the key technique for DIAL to measure atmospheric CO₂.