| The development of modern optical related manufacturing industry is closely related to optical detection technology.With the rapid development of lithography,astronomy and aerospace,machine vision and other hot fields,the requirements for optical detection of large aperture and long optical path systems are becoming higher and higher.At present,the main means of high-precision nano optical detection is to detect the test elements through interferometer.In this paper,a new dynamic interferometer with TP（twin PBS）structure as the interference core is proposed,which provides a new and feasible solution for synchronous phase-shift interferometry.In this paper,the generation mechanism of parasitic fringes introduced by PBS adhesive layer in the traditional Michelon measurement optical path is studied,and the optical path requirements for eliminating parasitic fringes are discussed.Taking the Mach Zehnder optical path structure as the starting point,the TP interference core composed of double PBS is invented by integrating the polarization optical requirements of synchronous phase shift,the requirements of open external measurement arm,compactness and convenience of adjustment.The test beam and reference beam are separated/reflected only on the coating surface in PBS,which meets the demand of eliminating parasitic stripes in the bonding layer.The core optical path of TP dynamic interferometer is designed to be compact and the adjustment process is integrated,and the adjustment steps are compressed;A practical dynamic interferometer composed of light source module,polarization interference module,imaging module and point-to-point module is used to measure the standard spherical mirror.Through the analysis of repeated measurement results,the test repeatability of the system is improved=1.229),=0.399),indicating that the measurement repeatability of the system is good.Then the optical path structure of the off-axis three mirror system is built to realize the precise measurement of the extremely weak reflection optical system of the off-axis three mirror system before coating.The polarized light transmission model is constructed by using Jones matrix,and the principle of the new spectroscopic core dynamic interferometer is described.The TP dynamic interferometer is simulated by ZEMAX software.The systematic errors of TP dynamic interferometer are analyzed and calculated,and the effects of the errors of wave plate,polarization spectroscopic prism and reference mirror on the measured wavefront are given.This paper analyzes the influence of spatial mismatch error of polarization CCD camera on the measurement results,the phase demodulation method based on pixel mask scheme used in this paper is given. |
