再入射离轴积分腔输出光谱干涉噪声处理方法

Method of suppressing interference noise for re-injection off-axis integrated cavity output spectroscopy

离轴积分腔输出光谱(OA-ICOS)技术具备灵敏度高和环境鲁棒性强等优点。引入再入射方法后,OA-ICOS的信号功率得到有效提升,缓解了探测灵敏度高度依赖光源功率的问题,让使用低功率光源和高反射率腔镜搭建高灵敏度OA-ICOS成为可能。但由于该方法特有的光学结构,探测信号中往往掺杂较为强烈的干涉噪声。针对干涉问题,设计并搭建了一套再入射OA-ICOS装置,测量了实际大气CO2,对再入射结构引入的噪声进行了分析,提出了扰动再入射结构的应对方法.结果表明:扰动方法使噪声信号幅值由原来的467.3 mV降低为61.2 mV,降低了7.63倍。该方法成本更为低廉,且实现更容易。

Off-axis integral cavity output spectroscopy(OA-ICOS) has the advantages of high sensitivity and strong environmental robustness.After the re-injection method is introduced,the signal power of OA-ICOS is effectively improved.It alleviates the problem that the detection sensitivity is highly dependent on the power of light source,and makes it possible to use low-power laser and high-reflectance cavity mirror to build the high sensitivity OA-ICOS.However,due to the special optical structure of the method,the detection signals tend to be doped with relatively strong interference noise.For interference problem,a re-injection OA-ICOS device is designed and built to measure the actual atmosphere CO2.The noise introduced by the re-injection structure is studied,and disturbance method is proposed to decrease the noise.Results show that the disturbance method reduces the amplitude of noise signal from the original 467.3 mV to 61.2 mV,which is 7.63 times lower.The method has the advantages of lower cost and easier implementation.