Study of wavefront reconstruction based on four-wave lateral shear interferometer method

Shear interferometer measurement method is one of main techniques in optical interferometry metrology. A shearing interferometric detection system is presented in order to obtain the three- dimensional profile of wavefront. A aperture and chessboard grating were used to divide the measured wavefront into four wavefronts, and two coherent wavefronts form an interferogram. The theoretical model of shearing interferometric detection system based on Fourier Optics and light intensity transmission equation is structured. According to the Fourier transform algorithm, an algorithm of shear interferogram processing is presented. Finally, the measured wavefront can be reconstructed. The transient wavefront detection system was applied to reconstruct the transient wavefront automatically. Experiments show that the apparatus offers higher accuracy, which satisfies the need for the practical applications. The measured results are in good agreement with the reconstructed wavefronts from SID4 wavefront sensor. The system can be applied to transient wavefront reconsitution.