基于子孔径拼接技术的大尺寸光学材料均匀性检测系统

Measurement System of Optical Homogeneity of Large-Size Optical Material Based on Subaperture Stitching Technique

为实现大尺寸光学材料折射率均匀性的高精度、低成本检测,提出一种基于子孔径拼接技术的干涉绝对测量方法,并研制了一套由Zygo干涉仪、五维气浮调整平台、子孔径拼接软件、计算机等组成的测量计算系统。待测件安放在精密的五维气浮调整架上,通过移动调整架来对各个子孔径区域进行精密检测,再利用子孔径拼接软件自动拼接计算出全口径待测件的光学均匀性分布。对直径为300mm的石英待测件进行了口径为180mm的8个子孔径拼接检测实验,并将拼接所得结果与全口径干涉仪直接测量的结果进行了分析和比较,波面峰谷值相对误差为0.21%,光学均匀性值相对误差为0.23%,精度与大口径干涉仪直接测量的精度相当,实现了绝对检验下的平面类波前子孔径拼接技术的实用化。整套系统集光、机、电、算于一体,操作简便,测量精度高。

In order to realize high-precision,low-cost measurement of optical refractive-index homogeneity of large-size optical material,an interference absolute testing method based on subaperture stitching technique is proposed and a measurement system comprised of a Zygo interferometer,a sophisticated five-dimensional adjustment air-floatation platform,subaperture stitching software and a computer is developed.The optical component under test is placed on the five-dimensional adjustment platform and all subaperture areas of the component can be measured precisely by moving the platform.Then optical-homogeneity distribution of the whole optical component is calculated out automatically by subaperture stitching software.In the experiment,a 300 mm quartz optical component is measured in stitching mode of eight subapertures by using a 180 mm interferometer.The stitching result is compared with the direct measurement result obtained by using full-aperture interferometer.The relative error of wavefront peak-to-valley value is 0.21%,the relative error of optical homogeneity value is 0.23%.This precision can be compared with the precision of directly measured result.The practicability of subaperture stitching technology of plane-type wavefront measured by using absolute test method is realized.The whole system integrates optics,mechanics,electrics and computer together and can be operated conveniently with high accuracy.