High-fold optical subdivision blazed grating interferometer based on Mach-Zehnder interferometer

A blazed grating interferometer with high-fold optical subdivision is proposed based on the optical path design of Mach-Zehnder interferometer. In the designed measurement system, multiple diffractions are achieved on the blazed grating surface, fully leveraging the high diffraction efficiency of the blazed grating and avoiding the presence of non-coplanar beams. Furthermore, in order to avoid beam deformation resulting from multiple diffractions, the light path structure returning along the same path is constructed, and this design doubles the optical subdivision fold factor. The experimental results show that 14-fold optical subdivision can be realized in this measurement system, and the maximum calibration difference can reach 34.47 nm within a 0.2 mm travel and 101.07 nm within a 2 mm travel. The designed blazed grating interferometer has the characteristics of a simple structural layout, high-fold optical subdivision and high measurement performance, which lay the groundwork for actual product development.