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In order to measure the aspherical transmission wavefront of large aperture optics with wedged angle, three compensators were fabricated based on theories of geometrical and diffraction optics, a single null lens and two computer-generated-holograms (CGH) by different frequecy carrier. The results show that both refraction null compensator and diffraction plate can achieve high-precision wavefront measurement of large aperture aspherical optics, the difference of wavefront measured by refraction and diffraction methods is better than 0.01λ(RMS) in the effective aperture area. Because of the measure beam deviation caused by the optic wedge, the results is very sensitive to parts position and gesture. Due to a smaller divergence angle and extra alignment/fiducial area for precision adjustment, the primary aberrations of tilted CGH measurment can get a better control than that of null compensator. Precise control or adjustment of compensator is critical for aspherical wavefront measurement. Null compensator lens can easily induce regulation error while CGH method could cause mid-frequency disturbance.
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