The impact of polarization on grating performance of the lateral shearing interferometer

摘要

With the development of modern precision optical systems, optical detecting system requires the accuracy of wavefront aberration to arrive to sub-nanometer level. When the incident field with polarization information, the polarization information will have a significant impact on the accuracy of measurement results by interacting with polarization-sensitive optical components in the lateral shearing interferometer. We propose the integrated interferometer wavefront sensor (IIWS) system, which is based on the traditional lateral shearing interferometer. This wavefront is sheared by a two-dimension diffraction grating in our system, the two-dimension diffraction grating is the key element to analysis the metrology performance. When using a different grating period and shearing direction, the wavefront shearing and phase shifting with polarization information will produce different error, moreover the impact will vary in the different diffraction orders. In this paper, calculation is based on the finite difference time domain (FDTD) algorithm. When calculation of different polarization state distribution of the incident field, the interaction analysis of shearing phase shifted grating and incidence light play an important role in error analysis. Finally we can get the effect of polarization for grating performance.