Absolute measurement method of homogeneity of optical flat

Abstract

The invention discloses an absolute measurement method of homogeneity of an optical flat, belonging to the field of optical interferometry. The method comprises the following steps: 1. putting detected optical flat into a measurement light path, and measuring the wave surface deviation of interference cavities formed by the front and back surfaces of the optical flat; 2. putting the optical flat into an interferometry cavity formed by reference optical flat working surfaces and reflection optical flat working surfaces, and measuring the aberration of waves reflected by the optical flat; 3. removing the detected optical flat from the interferometry cavity, and measuring the wave surface deviation of the interferometry cavity formed by the reference optical flat working surfaces and reflection optical flat working surfaces; and calculating the homogeneity distribution of the detected optical flat according to the three measurement results. The method has the advantages of fewer steps and high accuracy, is simple to operate, and can be used for high-precision measurement of refractivity homogeneity distribution of the optical flat for laser working materials and spacecraft window glass.

Description

technical field [0001] The invention belongs to the technical field of optical interference measurement, in particular to an absolute measurement method for the uniformity of optically parallel flat glass. Background technique [0002] Optical uniformity is an important indicator of optical materials. With the continuous development of optical processing and manufacturing technology, its accurate measurement has become an important topic. At present, there are two types of measurement methods for the uniformity of optical materials: qualitative measurement and quantitative measurement. Quantitative measurement can be divided into general measurement and absolute measurement. General measurement refers to the measurement that the test results include the wavefront error of the sample polishing, the wavefront error of the mounted plate, and the wavefront error of the standard mirror of the test instrument. Absolute measurement refers to the measurement that removes the sample...

AI Technical Summary

Problems solved by technology

[0004] In summary, measuring the uniformity of optical materials with a pair of collimated light tubes is a qualitative measurement, and quantitative results cannot be obtained; using general interferometric methods to measure, the final results include the front and rear surface wavefront errors of the sample and the interferometer The wavefront error of the standard mirror, or the wavefront error including the working surface of the reference flat crystal; using the immersion method to measure the uniformity of optical materials, it is necessary to prepare a refractive index liquid consistent with the refractive index of the object to be tested, which is inconvenient to operate; using holographic differential interference method, interferometer transmission measurement method and wavelength tuning interferometry method are all absolute measurement methods, but there are many measurement steps and the operation is more complicated

Images