Study On Ion Beam Polishing Technology Of Fused Quartz Plane Element

With the continuous development of modern optical element manufacturing technology and increasing social demand,the requirements for surface quality are more stringent for both engineering optics represented by strong lasers,short-wave optics,and information microelectronics represented by large-scale integrated circuits.It is urgent to explore the limit of high precision optical element surface manufacturing technology.Ion beam processing is an atomic-level material removal and non-contact processing method.As an advanced optical element manufacturing technology,it can not only correct the surface shape error,but also the surface micro-topography,and finally achieve the processing of ultra-smooth surface.This paper is based on the basic theory of ion beam sputtering etching and combines the experiment to deeply analyzed the microscopic action mechanism of fused quartz surface during ion beam bombardment.The main contents include the following aspects:1.The mechanism of ion beam sputtering etching is analyzed,the removal characteristics of ion beam are determined by experiment,and a mathematical model is established.The micro-shaping behavior and the evolution mechanism of micro-nano-scale roughness on the surface of the materials accompanied by the physical sputtering process of ion beam were deeply studied.The change of process parameters during ion beam polishing will obviously lead to the change of the microstructure of element surface.The mapping relationship between ion energy,incident angle,number of ions and sputtering yield of fused quartz materials is analyzed by software simulation.2.Based on the Sigmund sputtering theory and the BH theory,the evolution law of micro-nano-scale surface morphology under the action of ion beam is revealed,and the essential reason for the surface smoothness of optical element under the action of roughness effect and smoothing effect during ion beam sputtering is explained.3.The RF ion source is the core of ion beam processing.The effect of its operating parameters on the surface of fused quartz is studied.The orthogonal experiment and the AFM test results were used to explore the evolution of the surface roughness of fused quartz under various factors.The results show that:Ion beam bombardment cannot effectively suppress IF errors on the surface of fused quartz,while under certain sputtering conditions,the nano-scale roughness of the fused quartz surface was significantly improved.4.The mechanism of microstructure generation under the action of ion beam was explored.Using the self-developed equipment,experimental methods are used to analyze the generation rules of micro-nano structures on the surface of optical elements under ion beam tilt processing.Overall,the relationship between micro-nano structure generation and sputteringparameters during ion beam processing is revealed,these provide some technical support for processing the super smooth surface.