Fringe contrast ratio-adjustable large-numerical value bore diameter point-diffraction interference device and method

Abstract

The invention discloses a fringe contrast ratio-adjustable large-numerical value bore diameter point-diffraction interference device and a fringe contrast ratio-adjustable large-numerical value bore diameter point-diffraction interference method. A linear polarization laser generates a parallel light through a 1 / 2 wave plate, a first 1 / 4 wave plate and a collimating and beam expanding system, the parallel light is focused on an interference pinhole of a point-diffraction plate through a microobjective, a detection wave front W1 is focused at an O point after passing through a second 1 / 4 wave plate to obtain a spherical wave front W1', a reflected light wave reflected by a spherical surface to be detected passes through the second 1 / 4 wave plate again to obtain a circularly polarized light of which the rotation direction is opposite to a reference wave front W2, and is reflected through a metal reflecting film on the point-diffraction plate, the detection wave front W1 and the reference wave front W2 are converged to change into a plane wave through a collimating lens, an interference fringe is obtained on a detector through a third 1 / 4 wave plate, a polarization analyzer and an imaging lens, and the detector timely acquires a corresponding interference pattern. The device and method simplify the point-diffraction interference adjusting difficulty, and provide a feasible method for the high-precision detection of a large-numerical value bore diameter spherical surface, particularly of a low-reflectivity spherical surface.

Description

technical field [0001] The invention belongs to the technical field of optical measurement, and in particular relates to a large numerical aperture point diffraction interference device and method with adjustable fringe contrast. Background technique [0002] With the continuous development of optical processing technologies such as lithography machines, high precision requirements are put forward for optical detection instruments. Traditional interferometric detection systems such as Tyman-Green interferometers and Fizeau interferometers use standard lenses with high surface accuracy to obtain reference wavefronts. However, due to limitations in optical manufacturing and processing costs, the accuracy of traditional interferometric detection systems They are all limited by the surface shape accuracy of standard lenses. At present, the peak-to-valley value of surface shape detection accuracy of commercial interferometers such as Zygo and Wyko in the United States can only re...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the existing pinhole point diffraction interferometer is difficult to realize the high-precision surface shape detection of a large numerical aperture spherical surface, especially a low-reflection spherical surface in the case of a large-scale diffraction pinhole, and to provide a fringe contrast that can Tuned large numerical aperture point diffraction interferometry device and method

Images