Research On Defects Detecting Method Of Optical Component Based On Micro Confocal Raman

With the continuous development of various optical technologies and the continuous expansion of application fields,the quality requirements of optical products in modern industries are becoming more and more stringent.Surface defects will inevitably occur during the processing and use of optical components,which will seriously affect the performance of the entire optical system.The visual inspection method used for a long time is not only difficult to meet the industrial needs of large-scale detection,but also difficult to detect some small defects.Therefore,the research on defect detection methods is of great significance.Based on this,a method for defect detection of optical components is developed in this paper.First of all,the scattering effect of surface defects of optical components is analyzed.Aiming at the problem that the scattered signals of small defects are easily concealed and ignored,a method based on micro confocal Raman spectroscopy is proposed,which to amplify the scattering effect of defects and to realize the detection of surface defects of components.Next,the reliability of the method is experimentally verified by using gradient scratches of standard width on the sample.During the research,the Raman spectrum of the scratch area was collected and the characteristic peak intensity was extracted for splicing imaging.The imaging results of the two sizes of sampling spots were analyzed,and the detection effects at different focal depth positions were compared.The results show that the Raman characteristic peak intensity of optical component will be greatly reduced or increased by defects on the surface.In this way,surface defects of components can be accurately detected by analyzing the variation trend of characteristic peak intensities in the collected data.In this way,the position distribution and area size of the defects can be accurately identified by analyzing the variation range of characteristic peak intensity of the Raman spectrum during the scanning process,and the detection of micron-scale surface defects can be effectively realized.In view of the frequent damage of components under high-power lasers,the characterization method of component damage based on the detection of surface scratch defects by micro confocal Raman is further studied in this paper.The KDP crystal material was selected for experiments,and the defect-free and defective area of the crystal plane were irradiated with high-power laser at equal intervals.Then,the peak intensity and peak position of Raman spectrum characteristic peaks of different sampling nodes were extracted,which to analyze the characteristics of laser damage.The results show that laser damage can be easily induced by surface defects,and the melt spots will be formed in severe cases.In addition,various imaging results will be presented by different characteristic peak data,among which the location and size of defects on the crystal surface can be reflected by the results of the 904cm-1 peak,while the damage can be reflected by the results of the 1139 cm-1 peak.By analyzing the variation range of the peak intensity of different characteristic peaks and the variation of the characteristic peak position of the Raman spectrum during the scanning process,the position distribution of the crystal laser damage can be determined,and the detection of the laser damage on the surface of the component is effectively realized.