[00126366]基于高密度光栅的高分辨率光栅干涉仪

一种基于高密度光栅的高分辨率光栅干涉仪,包括线偏振光源、偏振分束器、第一反射镜、第二反射镜、第三反射镜、第四反射镜、第一四分之一波片、第二四分之一波片、数据采集和处理及控制单元,由非偏振分束器、处于正交双频线偏振光45度放置的第一检偏器及对应的第一探测器、处于正交双频线偏振光45度放置的第二检偏器及对应的第二探测器构成的双频外差干涉光电探测单元,以及自准直装置。本发明将高密度光栅设计成负一级高衍射效率;进而采用细分光栅使得光束被标尺光栅多次衍射,并且最终垂直入射到反射镜上实现光路原路返回,通过光束多次经标尺光栅衍射,获得高光学细分倍数,从而提高光栅干涉仪的分辨率。 | A high-resolution grating interferometer based on high-density gratings comprises a linear polarization light source, a polarization beam splitter, a first reflector, a second reflector, a third reflector, a fourth reflector, a first quarter wave plate, a second quarter wave plate, a data acquisition, processing and control unit, a double-frequency heterodyne interference photoelectric detection unit and an auto-collimation device, wherein the double-frequency heterodyne interference photoelectric detection unit is composed of a non-polarization beam splitter, a first polarization analyzer placed on orthogonal double-frequency linearly polarized light by 45 degrees, a first detector corresponding to the first polarization analyzer, a second polarization analyzer placed on the orthogonal double-frequency linearly polarized light by 45 degrees and a second detector corresponding to the second polarization analyzer. The high-density gratings are designed to have negative first-class high diffraction efficiency. Thus, subdivided gratings are adopted, so that light beams are diffracted by a scale grating many times and finally are vertically reflected to the reflectors, and light paths return by the way that light paths come; the light beams are diffracted by the scale grating many times, so that a high optical subdivision multiple is obtained, and the resolution of the grating interferometer is improved。