Mathematical modeling analysis on a small and compact two-dimensional CGLSI interference system

When using interference wave front to detect density field, it is better to have an interference system which is small and compact so that different directions of wave fronts can be obtained to reconstruct the density field to be detected. A two-dimensional CGLSI (Cross Grating Lateral Shearing Interferometer) system which consists of a two-dimensional cross grating and a two-dimensional order-selecting window used as a filter is presented in this paper. Lateral shearing interferogram of two orthogonal directions (X and Y) each other can be obtained by using this system. With the advantage of anti-vibration and no reference surface, lateral shearing interferometer is suitable to inhibit external environment disturbance. In this paper, analysis and simulations have been conducted on grating constant from geometrical optics and physical optics using Fresnel approximation method respectively based on lateral shearing rate, windows' distance in two-dimensional order-selecting window and layout of the system which concludes the best option for grating constant is d = 25 mu m. The most optimized design of size and distance for windows in two-dimensional order-selecting window has been carried out on the basis that complex amplitude distribution can go through the filter so that there is no distortion on wave front. All designs have gone through computer simulation and fit into the requirements for the designs.