Detection and data processing of diffractive optical element

Diffractive optical elements (DOEs), with their excellent optical properties, can modulate the ideal wavefront, and have greater advantages in correcting chromatic aberration than spherical or aspherical optical systems.The difficulty in the processing of DOE lies in the fact that its processing accuracy requires not only that the surface shape of the aspherical substrate satisfies the accuracy requirements, but also that the phase saltation position and the height of the diffractive structure satisfy the requirements.Due to the discontinuity of the surface and the phase saltation position, the traditional detection method is difficult to meet the requirements.The detection error source of the profiler was analyzed, and the machining error data was analyzed in combination with the detection data. Based on this, the data processing was performed. The error data obtained by this method was applied to the part processing, and the surface shape error of the 120 mm diffractive surface was 0.539 μm.