Detection and Classification Method for Surface Defects of Large Aperture Optical Components

Abstract

The invention discloses a method and a device for detecting and classifying surface defects of a large-aperture optical element. The large-aperture optical element is irradiated by using a high-intensity light beam and a low-intensity light beam; the high-intensity light beam and an absorption defect interacts to generate fluorescent light; the low-intensity light beam and a non-absorption defect interacts to cause light beam scattering; and information of the absorption defect and information of the non-absorption defect of the large-aperture optical element can be obtained by respectively detecting the fluorescent light and the scattered light. According to the method and the device, by an inner full-reflection type illumination mode, a plurality of regions in the large-aperture optical element are synchronously illuminated and detected, so that the detection efficiency is improved. At the detection end, only the surface defects and sub-surface defects are detected by an imaging system with a small focal depth or a confocal imaging method. The method and the device are suitable for optical lossless flaw detection, optical precision detection, optical microimaging and defect analysis, and in particular suitable for a plurality of fields of surface and sub-surface defect detection of a large-aperture transparent optical element in a high-laser system.

Description

technical field [0001] The invention relates to the field of optical material defect detection, in particular to a method for detecting and classifying surface defects of large-diameter optical elements. Background technique [0002] For many optical materials, such as fused silica glass and KDP crystals, which are commonly used in strong laser systems, surface and subsurface defects and contamination will inevitably be introduced during material processing, such as cutting, grinding, polishing, etc. , so the optical quality of its surface and subsurface is often much worse than the intrinsic properties of related materials, so that the surface and subsurface of related components become the bottleneck limiting the performance of components in many applications, such as the most powerful laser system. Weak link that is easily damaged by laser light. [0003] For the surface and subsurface defects of optical materials, they can usually be divided into absorption defects and ...

AI Technical Summary

Problems solved by technology

[0004] Some defect detection methods commonly used at present, such as high-resolution scattering measurement method, high-resolution fluorescence measurement method, atomic force microscope, scanning tunneling microscope, near-field optical microscope, high-resolution photoacoustic microscope, and various high-resolution photothermal microscopes, etc. , only a certain type of defect can be effectively detected: the high-resolution scattering measurement method is mainly sensitive to the inhomogeneity caused by the optical refractive index or the surface shape defect, and it is difficult to be used for the analysis of the absorption defect

High-resolution fluorescence measurements are good at detecting optically absorbing defects, but are insensitive to non-absorbing defects

Photoacoustic and various photothermal microscopy methods can effectively detect absorption defects, but cannot be applied to non-absorption defects

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