Nondestructive testing method for optical glass polishing sub-surface damages

Abstract

The invention discloses a non-destructive testing method for optical glass polishing sub-surface damages. The method comprises the following steps of: preparing a non-destructive base at first, and then determining an incident angle for ellipsometry detection; calculating the optical constant of the non-destructive base according to ellipsometry parameters measured with the incident angle for ellipsometry detection, wherein the non-destructive base is defined as a substrate-environment structure, and a standard dielectric function is taken as a material physical model; defining a sub-surface damage surface of a sample as a multi-film optical model which comprises air, a coarse surface layer, a resedimentation layer and a substrate; building a multi-film material physical model through a mixed material effective medium model based on the multi-film optical model, and measuring the surface roughness and the depth distribution rule of surface sedimentation substances of the sample by virtue of the optical constant of the non-destructive base; and finally, carrying out inverse operation by a regression algorithm according to the ellipsometry parameters of the sample measured with the incident angle for ellipsometry detection, thus obtaining the depth of the sub-surface damage layer. The testing method is accurate, reliable, quick, efficient, flexible and controllable.

Description

technical field [0001] The invention relates to a method for detecting damage on the surface of an optical element, in particular to a method for detecting damage depth on an optical glass polished subsurface Background technique [0002] The existence of subsurface damage directly reduces important performance indicators such as the service life, long-term stability, coating quality, imaging quality, and laser damage threshold of optical components, especially polished subsurface damage such as redeposited impurities, plastic scratches, and microcracks. It will cause fatal damage to optical components in the environment of strong laser and high energy concentration. The characteristic scales of the above-mentioned polished subsurface damage are small (the plastic scratches are at the nanometer scale, and the concentration of polishing impurities is at the ppm level), and the forms are diverse, and the mutual coupling is difficult to distinguish effectively (the redeposited ...

AI Technical Summary

Problems solved by technology

However, how to improve the detection accuracy of the quasi-polarization angle technology for amorphous optical materials, especially how to use the quasi-polarization angle technology to establish and improve The optical model of ellipsometric detection and the physical model of materials are still to be further studied

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