Centroid shift analysis of microlens array detector in interference imaging system

Most CCD imaging detectors integrated microlens arrays (MLAs) to increase fill factor and sensitivity. However, they also introduce spot calibration issues with the inconsistency of spot geometry center and intensity distribution center. We setup theoretical and experimental models to research the problem of centroid shifting. According to the Seidel and Zernike coefficients of the optical model, we analyze main aberrations of microlens. In “Chief Ray” and “Centroid” reference frames, centroid shift numerical value is calculated with Geometric Ensquared Energy (GEE). Based on pentaprism test for 8.4 m mirror segment, we conduct spot imaging experiment in interference system. Spots images are obtained, and two-dimensional centroid algorithm processing is performed on them to get the analog experiment values of centroid movements. The results show that the MLA placed in KAI‐16000 imaging detector causes the spot centroid to move. When there is a 14° (or −14°) angle of incident ray, the shifting values are about 1.46 μm in simulation and 2.18 μm in experiment. Our research makes a contribution to the compensation of calibrated error in metrology technology. We also prove that a significant portion of the shift comes from the low order aberration of microlens.