Designing a 3D Confocal System

Abstract

There are countless types of off-axis mirror systems. A plane-symmetric system, a classic off-axis system, is relatively low complexity, due to its plane-symmetric property. Although a 3D system is more complicated, it gives us more degrees of freedom to fit in different volumes. In this thesis, we provide a method to design a 3D mirror system. We will start with the introduction of the plane-symmetric wave function and the 3D system as well as their aberration coefficients. Then we will dive into the method of calculating the aberration coefficients to understand the system and the method of designing a 3D system. Because a 3D system aberrations contain both axially and plane-symmetric aberrations, we have our own macro programs written in two different methods to calculate the aberration coefficients of a 3D system. One is adding the aberration coefficients contributed from each surface. The other one is extracting the aberration from the OPD real ray tracing. With those two algorithms and their macros, we are able to pay close attention to the dominant aberrations and release the proper variables for optimization. In this way, we can understand the system and its limitations better and also the trade-off between different aberrations and other system parameters.