Research Progress of Ultra-Precision Measurement of Optical Surfaces for Manufacturing

Ultra-precision measurement is the precondition for optics manufacturing. Null test is still the fundamental principle for high-precision measurement of optical surfaces. Computer generated holograms are indispensible for null test of complex surfaces including freeforms. Problems oriented to manufacturing are discussed with emphasis including the principle of CGH null test and its ghost disturbance orders of diffraction, projection distortion correction, uncertainty, and absolute test. The limit of CGH null test is also presented along with possible solutions. For challenges in measuring the dynamically evolving local big errors generated during the manufacturing process, subaperture stitching test and adaptive null test methods are discussed. The progress of in-situ interferometry for machining is then briefly introduced. Finally a prospect of optical surface measurement is presented with focus on ultra-high precision measurement and traceability, macro-micro multiscale measurement of hybrid optics, independently controllable instruments for optical surface metrology, and in-situ integration.