Design of TMC wavefront coding system based on user defined surface mask plate

In wavefront coding optical system, with the traditional cubic mask plate (CMP) which owns several extension times of depth of focus (DOF), it is difficult to manufacture. With the symmetrical surface type mask plate which can be machine relatively easily, but it presents small multiples of the extension of DOF. In this paper, it makes a presentation of mask plate design by user defined surface(UDS) type where it has an easy mechanical process and several multiples of extension of DOF. It presents the analytic expression by calculation and its DLL data file which is adapted to ZEMAX. It also performs a simulation experiment based on the three mirror Cassegrain(TMC) wavefront system. The experiment results indicate that instead of the traditional mask plate, the UDS surface mask plate can obtain a larger ratio of extension of DOF and increase the valuable types of mask plate surfaces. What is more, it decreases the surface mechanical difficulty compared to the asymmetrical surface mask plate. The type of UDS surface has the unique design and the convenience manufacturing, which is of great value in both application and research.