Curved CGH design techniques for aligning reflective optical system

In order to realize fast and effective alignment of reflective optical systems, a computer-aided alignment method based on CGH(computer-genereted hologram) is proposed. The method is based on the CGH that realizes zero compensation, phase modulates the spherical light wave emitted from the interferometer, makes it perpendicularly incident on the optical element to be aligned, and converts the misalignment information brought back by the reflected light into Zernike coefficients, which is used to guide the alignment work. This paper is based on an infrared coaxial reflective system to carry out a comparative design study of CGH applied to alignment. Due to the use of different areas of a CGH to align multiple optical elements, different optical elements need CGH to provide a large difference in the degree of optical focus, the design and processing of the CGH is more difficult. The design found that the minimum stripe width of the planar CGH is 4μm, and the method of single point diamond turning (SPDT)can not achieve its machining accuracy, while the minimum stripe width of the curved CGH is 57μm, and it can be processed by SPDT.