激光外差技术是一种高灵敏度的光谱探测技术, 利用该技术研制的装置易于集成化小型化, 可以进行地基或星载的地球大气或天文观测。 基于激光外差光谱测量技术, 结合自研的太阳跟踪仪建立了一套高分辨率整层大气透过率测量系统, 系统分辨率约为0006 cm-1。 该系统利用太阳光和红外激光在非线性探测器中进行光学混频, 通过对获取的混频信号进行电子学滤波和平方率探测, 获得了高光谱分辨率的外差信号。 采用Langley-plot定标法对测量系统进行定标, 获取了仪器标定常数和对应的大气总光学厚度, 实现了中红外波段整层大气透过率的实时测量。 同时, 将实测整层大气透过率与MODTRAN50软件仿真计算的结果进行对比分析, 两者的一致性较好。 分析表明该测量系统具有很高的分辨率并且性能稳定可靠, 在大气科学、 天文观测和激光大气传输等研究领域具有广阔的应用前景。

Laser heterodyne technology is a highly sensitive laser spectroscopy technique which can be integrated. It has the potential to develop a compact ground or satellite based radiometer for Earth observation and astronomy. Based on the laser heterodyne technology, a set of high resolution laser heterodyne detection system was established together with a solar tracker. The spectral resolution of the system is about 0006 cm-1. Sunlight is superimposed with infrared laser light in a nonlinear detector. The signals pass through an electronics filter and a square-law detector, then the high-resolution heterodyne signal is extracted. In terms of the field measurement, Langley-Plot Calibration method was used to calibrate the system first, then total atmosphere transmittance of mid-infrared was measured. The calibration constant and corresponding to the atmospheric total optical thickness were presented. According to the comparison between the results of heterodyne measurement system and that of software MORTRAN50 calculation, good agreement was obtained. It is shown that the system has high spectral resolution which can be applied to atmospheric transmittance measurement. Besides, the system also shows potential applications in atmospheric sciences, astronomy, laser propagation through the atmosphere and other areas.