Study On Subsurface Damage Light Scattering Detection Method For Optical Components

With the rapid development of modern optical industry,ultra-precision optical products have been widely used in various high-tech industries,especially large-size optical components in aerospace and other fields have a large number of needs.Due to the complex and difficult manufacturing process of precision optical products,high-quality surfaces are critical to finished products,and the detection of subsurface damage is particularly critical.In this paper,the scattering characteristics of sub-surface damage are analyzed based on light scattering theory.The sub-surface damage light scattering detection method is studied based on the confocal microscopic measurement platform.The main research content includes:This paper introduces the structure,origin and light scattering mechanism of sub-surface damage,describes the measurement principle of confocal microscopy system,analyzes the influence factors of scattered light intensity and theoretical basis for the calculation of scattered light intensity.The damage model was established and the scattering simulation experiment was performed.The basic principle of the finite-difference time-domain(FDTD)method for the numerical calculation of damage scattering is introduced.A common type of single-damage scattering model is established,the process of focused light detection is simulated,and the light caused by subsurface particles and micro-cracks is studied.Field distribution and variation of scattered light intensity.A laser confocal microscopic measurement platform was constructed to perform measurement experiments on samples with known damage,and a scattering model and detection simulation was established for the damage.The experimental results obtained by the two were consistent,and the correctness of the scattering model was proved to be further studied.The scattering properties of complex damage provide a theoretical basis.Based on the same measurement platform,the polished sample with complex damage was detected,and the damaged tomographic image was obtained.The distribution and depth of the sub-surface damage can be clearly seen.The consistent sub-surface damage depth was obtained through chemical etching and verified.Laser scattering confocal microscopy was used to test the effectiveness of subsurface damage.Through simulation analysis and experimental research,it can be confirmed that the laser scattering confocal microscopy method can perform nondestructive quantitative detection of subsurface damage of optical components.