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腔衰荡光谱技术(CRDS)由于其具有高灵敏度、高精度、装置简单等特点,被广泛应用于痕量气体检测、镜面反射率测量等领域。建立了一套基于连续波频率的腔衰荡光谱(CW-CRDS)装置,基于Pound-Drever-Hall(PDH)频率锁定技术将激光器的频率锁定到光学腔的纵模上,从而保证了激光功率到腔模的高效耦合。通过观测不同的声光调制器(AOM)关断频率对应的透射信号,得到光路最佳关断频率为60kHz。使用该系统测量了光学腔腔镜的反射率,通过与非锁定情况下测量得到的结果进行对比,得出锁定后的结果漂移减小,误差也压缩为非锁定情况下的1/3。
Cavity ring-down spectroscopy (CRDS) is widely used in trace gas detection and specular reflectance measurement because of its high sensitivity, high precision and simple device. A CW-CRDS device based on continuous wave frequency was established. Based on Pound-Drever-Hall (PDH) frequency locking technique, the frequency of the laser was locked to the longitudinal mode of the optical cavity to ensure the laser power Efficient coupling to the cavity mold. By observing the transmitted signal corresponding to the turn-off frequency of different AOMs, the optimal turn-off frequency of the optical path is 60 kHz. The system was used to measure the reflectivity of the optical cavity mirrors. Compared with the results measured in the non-locking case, the result shows that the drift after the locking is reduced and the error is also compressed to 1/3 that of the non-locking case.