Using Twin-of Cgh For The Absolute Test Of The Spherical And Aspherical

With the development of optics, aspherical elements gain more and more use in optical systems. High-precision testing limits the use of aspherics as a crucial factor. The thesis carried on the research about a high-precision testing method of aspherics, the absolute testing of aspherics with Twin computer-generated hologram(Twin-CGH).Some researches had been done based on theoretical and experiments. The encoding method and fabrication of CGH were introduced, then, the methods for encoding two phase function in a Twin-CGH were elaborated. The extended absolute measurement of spherical surfaces with Twin-CGH which reconstructs two spherical waves with different optical powers was showed. The pattern error and figure error of Twin-CGH in different spherical waves were separated respectively and derived from each other. The derivative results were compared with experimental ones, and the difference-value were less thanλ/40(PV). The results demonstrate the feasibility of error transfer in Twin-CGH. Finally, with a specially designed Twin-CGH, the absolute testing of a high order asphere was done by seven measurements. The error contribution of the asphere was separated absolutely from all other systematic errors of the test setup, and a simple discuss on fabrication errors of CGH was made.