Research On Ion Beam Processing Technology Of Transmission Aspheric Laser Collimation Objectives

With the continuous development of technology in the field of optics,optical systems are demanding higher and higher face shape accuracy of key optical components,even to subnanometer level.Aspheric optical components have been widely used in industrial and commercial fields due to their advantages of improving optical system performance and simplifying system structure.Traditional optical processing methods are limited by their material removal mechanisms,and it is difficult to achieve nanometer-level precision behind the processing surface.In contrast,ion beam polishing technology has the advantages of noncontact processing,high processing accuracy and good determinism,which is suitable for high-precision polishing of aspheric surfaces.In this paper,the research on processing transmitted aspheric laser collimated objective lens using ion beam processing technology is carried out as follows:Firstly,according to the technical specifications of the transmission aspheric laser collimation objective,the optimized design of the optical system is completed,and the curvature of the ellipsoidal vertex of the aspheric mirror is 913.77 mm after satisfying the imaging quality requirements.one-dimensional search method is used to solve for the closest spherical surface of the aspheric surface to find the minimum material removal for spherical to aspheric surface,and the radius of curvature of the closest spherical surface is obtained as915.3 mm.Secondly,the process flow of aspheric optics is described;speckle etching experiments are performed on K9 optics used for transmission aspheric mirrors to obtain the removal function required for ion beam processing,linear scanning experiments are performed to verify the stability of ion source operation,and a batch processing method is proposed to reduce the effect of temperature effects on the removal rate of the optics.Thirdly,the dwell time solution is performed,and the linear system of equations method combined with the TVSD method is used to solve the approximate solution of the linear system of equations.Next,the simulation and processing of the dwell time for the K9 plane mirror is performed to verify the correctness of the dwell time algorithm.Finally,the transmission aspheric mirror is processed and inspected,using the image-free method as the inspection method for the transmission aspheric surface.A combination of large beam size for fast convergence of the surface shape error,small beam size for refinement and base surface preservation is used to process the transmission aspheric mirror to achieve the best shaping effect.After four iterations of processing,the RMS value of the transmission aspheric laser collimating objective converged to 0.028λ and the PV value reached 0.309λ,which can meet the processing accuracy requirements well and can realize the practical application of the transmission aspheric laser collimating objective.