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设计了一种新颖探测对流层二氧化碳气体的 1572nm 差分吸收雷达,它的发射系统基于脉冲的种子注入 KTP 参量振荡器(OPO)。OPO 由 1064nm Nd:YAG 多模激光泵浦,转换效率 10%,重复频率 20Hz,OPO 的腔长由 PZT 单元和二氧化碳多通道吸收池精确控制,种子注入时,它可以产生单模窄带的信号光脉冲输出, 对应的空闲光输出仍然是多模。窄带 on 光源(线宽小于600MHz)对应于二氧化碳光谱的强吸收线,宽带 off 光源(150GHz)对应于光谱的弱吸收线。on 和off 双波长工作是通过对种子光的 10Hz 开关来得到的。雷达接收系统的核心是近红外光电倍增管和光子计数器,光电倍增管制冷到-60℃以降低其噪声。实验表明,该雷达的信噪比在 6km 以内大于 10 :1(10 分钟 6000 个脉冲累加)。
A novel 1572 nm differential radar for detecting tropospheric carbon dioxide gas was designed and its launch system was implanted with pulse-based seed into a KTP parametric oscillator (OPO). The OPO is pumped by 1064nm Nd: YAG multimode laser with conversion efficiency of 10% and repetition frequency of 20Hz. The cavity length of OPO is precisely controlled by PZT cell and carbon dioxide multi-channel absorption cell. When injecting seeds, it can generate single-mode narrow-band signal light Pulse output, the corresponding idle light output is still multimode. Narrowband on light sources (linewidths less than 600 MHz) correspond to the strong absorption line of the carbon dioxide spectrum and the wideband off light source (150 GHz) corresponds to the weak absorption line of the spectrum. On and off Dual-wavelength operation is achieved by switching the seed light to 10Hz. Radar receiving system is the core of near-infrared photomultiplier tube and photon counter, photomultiplier tube cooled to -60 ℃ to reduce its noise. Experiments show that the radar signal to noise ratio within 6km greater than 10: 1 (10 minutes 6000 pulse accumulation).