Subsurface measurement device and method based on total internal reflection and optical coherence tomography

Abstract

The invention discloses a subsurface measurement device and method based on total internal reflection and optical coherence tomography. The device includes a sequentially arranged light source system, a test platform and a microscopic analysis system, wherein the light source system includes sequentially arranged lasers, polarizers, Nomarski prisms, collimating lenses, first reflectors and second reflectors , the platform to be tested includes a rectangular prism, a refractive index liquid, and a sample to be tested, and the microanalysis system includes a high-magnification objective lens, a third mirror, a Nomarski interferometer imaging system, a fourth mirror, a fifth mirror, and an optical coherent The tomography system, the multi-dimensional precision electric control adjustment system includes a support platform, a microscopic system bracket, a three-dimensional micro-displacement component, a drive motor and a computer. The Nomarski interferometer microscopic imaging system and the optical coherence tomography system are both placed on the microscopic system bracket, and the total internal reflection rough positioning process and the optical coherence tomography process are respectively performed, that is, the two are combined to detect the components , Fast detection speed, strong reliability and high precision.

Description

technical field [0001] The invention relates to the technical field of subsurface damage measurement of optical elements, in particular to a subsurface measurement device and method based on total reflection and optical coherence tomography. Background technique [0002] Due to the existence of contact stress in the cutting and grinding process of optical components, defects such as impurities, scratches, and micro-cracks will occur below the surface of the components. At present, the measurement methods for subsurface damage in my country mainly include destructive and non-destructive measurement techniques, and destructive measurement methods are more commonly used. Traditional destructive measurement methods include: chemical etching, cross-section microscopy, angle polishing, magnetic Rheological polishing spot method, etc. The chemical etching method is easy to operate, low in cost, and highly intuitive, but the retest process is not easy to control and is easily affect...

AI Technical Summary

Problems solved by technology

The chemical etching method is easy to operate, low in cost, and highly intuitive, but the retest process is not easy to control and is easily affected by external factors, so the accuracy is not high; the cross-sectional microscopy method for measuring subsurface damage is simple in sample preparation and easy to implement, but the accuracy is low. The sensitivity and sensitivity are not high; the angle polishing method can be used for the measurement of micron-scale damage. It is difficult to measure accurately; the magnetorheological polishing spot method has a better damage depth amplification effect than the angle polishing method, so it is more suitable for the accurate measurement of low subsurface damage in the grinding and polishing stage

In addition to damage to components, destructive methods also have disadvantages such as time-consuming and dependence on experience

Non-destructive measurement methods include: focal laser scanning microscopy, total internal reflection, optical coherence tomography, etc. The longitudinal resolution of focal laser scanning microscopy is extremely high, but the detection range is too small; total internal reflection is The method based on intensity detection is relatively intuitive, but it can only be used for qualitative observation, and cannot accurately measure the depth and distribution of subsurface damage; the core of optical coherence tomography is Michelson interferometer, due to the subsurface damage on the optical surface The scattered light is very weak, which brings many difficulties to the acquisition and processing of interferograms

In addition, the current detection of subsurface damage of optical components is mainly a qualitative measurement of small apertures, and there are limitations in the detection of large aperture optical components, and the detection accuracy is unstable

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