Study On Plasma Cleaning Technology Of Organic Contaminants For Optical Elements

In large laser devices,the output laser of solid-state laser driver has the characteristics of high power and high density,so the load of components and the clean grade of vacuum device need to make strict requirements.However,under the action of strong laser,the aerosol content in the vacuum facility increases,and the laser damage resistance threshold of the optical element decreases,which leads to the decrease of the light quality of the laser device and the service life of the optical element.At present,the problem of organic contamination on the surface of large aperture optical components can not be completely solved by conventional cleaning methods.Low-voltage plasma cleaning has obvious advantages in less residue,less pollution and high efficiency,which provides a new idea and method for the treatment of optical components.At present,the problem of organic contamination on the surface of large aperture optical components can not be completely solved by conventional cleaning methods.Low-pressure plasma cleaning has obvious advantages in the aspects of no residue,no contamination and high efficiency,which provides a new idea and method for the treatment of optical components.The purpose of this paper is to study the low pressure plasma cleaning technology for large aperture optical components and the mechanism of plasma cleaning of organic pollutant dibutyl phthalate(DBP).Combined with the actual engineering conditions,the glow discharge plasma model was established to study the characteristics of plasma discharge,and the low-voltage plasma cleaning system was developed by combining the discharge model.Verify the cleaning mechanism,realize the effective recovery of the optical components related properties and the effective removal of organic pollutants,analyze the influence of cleaning on the components,and comprehensively evaluate the cleaning effect.Firstly,the microcosmic reaction system model of plasma and DBP was constructed.By analyzing the change level of bond energy in the reaction model,the main active particles involved in the reaction were determined.Finally,the mechanism of DBP decomposition induced by each active particle was analyzed,and the important intermediate products were identified,which prepared for subsequent experiments.Secondly,a low-pressure DC glow discharge model is constructed.The characteristics of particle density distribution,electric potential and electron temperature distribution in plasma are analyzed,and the relationship between them is studied.Combined with the results of the discharge model,a low pressure plasma cleaning system was developed and its normal operation was realized.Finally,a series of experiments on plasma cleaning of optical elements are carried out.The chemical state change of carbon element in the microscopic reaction process was analyzed,and the mechanism of cleaning organic pollutants by low pressure plasma was verified.The recovery effect of cleaning and the removal effect of organic contaminants were analyzed,the influence mechanism of cleaning on the surface properties of components was studied,and the cumulative effect of cleaning was analyzed.