The Design of Computer-Generated Holograms for Testing Unsymmetrical Optical Surfaces

It is a technical difficulty to test the unsymmtrical optical surfaces in non-contact methods. But we can do it using computer-generated holograms (CGH). The principle and design of the CGH have been discussed in the paper. Take the cubic suface as an example, The order separation of the CGH is analyzed theoretically and the simulation result of the order separation is given in the paper. We develop the binary process of the continuous CGH phase function and get the sample of the amplitude CGH. A CGH for testing a cubic phase plate with duty cycle 0.5 is fabricated by using e-beam lithographic techniques. In this situation, the contrast of the interference fringe pattern can achieve a level of 99.4% by calculation.