针对开放光路TDLAS(可调谐半导体激光吸收光谱技术)气体检测系统中, 由于角反射器在生产及使用过程中表面光洁度下降及大气传输扰动造成回波信号入射方向与接收透镜光轴非严格平行, 从而导致系统探测灵敏度下降的问题, 分析回波信号与菲涅尔透镜光轴夹角不同时的汇聚点偏移量, 设计了由圆锥体反射器和抛物面反射器组成的二次光学元件, 并运用TracePro光学软件对其参数进行优化。在回波光线-6°~6°入射角偏差范围条件下对优化设计的光学接收组件进行聚光特性模拟。模拟结果表明: 优化设计的光学接收组件接收角为4.9°, 光学效率为78.24%, 与单独菲涅尔透镜及菲涅尔透镜-复合抛物面聚光器(CPC)光学接收组件相比聚光性能明显提高, 适用于实际检测过程。

In the open-optic path tunable diode laser absorption spectroscopy(TDLAS) detection system for gas, due to the surface finish degeneration of corner reflector during production and using and the atmospheric transmission disturbance, the incident direction of echo signal and the optical axis of receiving lens are not strictly parallel, resulting in the decrease of the system detection sensitivity .Aiming at this problem,firstly the offset of convergence point with the incident direction of echo signal different from the the optical axis of the Fresnel lens was analyzed, then a secondary optical element consisting of a conical reflector and a parabolic reflector was designed and its parameters were optimized by TracePro software.Moreover,the condensing performance simulation under the deviation range of echo incident angle in-6° ~ 6° was carried out.The simulation results show that the receiving angle of the optimized optical receiving module is 4.9° and the optical efficiency is 78.24%,the condensing performance is obviously improved comparing to the independent Fresnel lens and Fresnel lens-compound parabolic concentrator(CPC),the optimized component is applicable to the actual detection process.