基于自动扫描光栅单色仪的光学腔色散测量

Dispersion Measurement of Optical Cavity Based on Automatically Scanning Grating Monochromator

通过引入自动扫描光栅单色仪,实现了快速色散测量,极大程度地降低了载波包络偏频慢漂对测量准确度的影响,降低了测量复杂度,提高了色散测量精度。以815nm钛宝石锁模激光器作为光源,以自建的八镜光学腔作为参考,对厚度约为6.35mm的熔融石英窗片的群延迟色散(GDD)进行了测量,结果与Sellmeier方程给出的理论值相差1.2fs2,不准确度仅为0.5%。测得八镜光学腔在常温常压状态下的GDD为28.8fs2,比理论值低约12fs2,原因可归结为8片腔镜镀膜的不均匀性。

With the introduction of an automatically scanning grating monochromator,the rapid measurement of dispersion is realized,which greatly reduces the influence of the slow drift of carrier envelope offset frequency on the measurement accuracy,reduces the experimental complexity,and improves the dispersion measurement accuracy.In the experiment,the 815 nm Tisapphire mode-locked laser is used as the light source and a home-made eight-mirror ring cavity is taken as a reference,the group delay dispersion（GDD）of a piece of 6.35 mm-thick fused silica plate is measured and the difference between the results and that from the theoretical value derived from the equation of Sellmeier is 1.2 fs2 with an only uncertainty of 0.5%.The GDD of the eight-mirror ring cavity under normal temperature and pressure condition is 28.8 fs2,smaller by 12 fs2 than the theoretical value,which is attributed to the coating inhomogeneity of the eight cavity mirrors.