Collimator is an important equipment with high accuracy in optical experiment and measuement. In order to improve
measuring accuracy, based on the particular aberration property of diffraction optical element, hybrid refractivediffractive
aberration correction method is put forward. In this paper, a hybrid refractive-diffractive method is compared
with conventional method with 80mm diameter, 500mm focal length and 550mm overall length. The resolution is less
than 4.3". Having been optimized, the maximum spot is 5.2μm, and the modulation transfer function (MTF) at
50lp/mm is over 0.8, better than conventional method.