用于位相缺陷检测的反射式剪切点衍射干涉仪

为了实现光学元件位相缺陷的大视场、高分辨率、瞬态检测,设计了一种基于无镜成像算法的反射式剪切点衍射干涉仪。该干涉仪通过在参考光与测试光之间引入横向错位量,形成高密度线性载频,利用快速傅里叶变换算法从单幅干涉图中提取待测波面信息,实现缺陷的瞬态测量。利用无镜成像算法抑制了缺陷的衍射效应,总结了有效的缺陷类型辨别方法。实验检测了强激光系统中的一块光学平晶,验证了所提缺陷类型判据的正确性。此外,采用反射式剪切点衍射干涉仪对一块激光毁伤的光学平板进行检测,测试结果与Veeco NT9100白光干涉仪测量结果相比,相对误差为2.1%。结果表明,该干涉仪能够有效应用于检测大口径光学元件的位相缺陷。

Reflective shearing point diffraction interferometer for phase defect measurement

In order to realize a large field, high resolution, and dynamic measurement of phase defects of optical components, a Reflective Shearing Point Diffraction Interferometer (RSPDI) was proposed. A lateral shear amount was introduced between the test and reference light to generate a high-density linear carrier frequency, and the information of the wavefront under the test was extracted from a single interferogram by an fast Fourier transform algorithm to determine the simultaneous measurement of the defects. The lensless imaging algorithm suppressed the diffraction effect of the defect, and the effective discrimination method of the defect type was summarized. In the experiment, an optical flat in a high-power laser system was detected by the RSPDI, and the correctness of the defect type criterion was verified. In addition, a laser-damaged optical plate was measured by the RSPDI and a Veeco NT9100 white light interferometer, with a relative error of 2.1%. The results indicate that the interferometer can be used to detect phase defects of large-aperture optical components effectively.