Theory and method of pulsed ion beam single crystal silicon reshaping based on controllable time-varying removal function

With the continuous improvement of optical performance requirements, weaponry, space observation, laser fusion, extreme ultraviolet lithography, and other fields of optical components of increasing precision requirements, the number of requirements is increasingly large, so the processing of optical components faces serious challenges. Pulsed Ion Beam Shaping is a non-contact optical component machining technology. Pulsed Ion Beam Shaping has the advantages of atomic-level machining accuracy and no edge effect. The ability of pulsed ion beam reshaping mainly depends on factors such as the stability of the removal function, the dynamic performance of the machine's motion axes, and the size of the removal function. At present, due to the difficulty of further improving the dynamic performance of the machine tool, a single beam diameter, and removal efficiency of the removal function for processing, trimming efficiency is not high, and can only be balanced according to the needs of trimming efficiency and accuracy. Thus, we proposed a pulsed ion beam reshaping processing method based on a controlled removal function to achieve the optimal beam diameter selected by the removal function according to the different reshaping face shapes, which improves the reshaping capability of the pulsed ion beam while reducing the additional material removal layer to ensure high processing efficiency. The main research on the shaping method based on the controlled time-varying removal function is carried out, the shaping model based on the controlled time-varying removal function and the residence time solution model are analyzed, the global optimization algorithm based on the error distribution of the surface shape and the removal function library, and the optimal combination of the removal function under the constraints is established, and the theory of the shaping of the controlled time-varying removal function is perfected, and the iterative genetic algorithms, variation and crossover design are used to find the optimal beam diameter according to different shapes of the surface, to improve the processing efficiency. The genetic algorithm is used to iterate the genetic algorithm at different processing points, and the mutation and crossover design is used to find the optimal solutions at different processing points, and the processing is carried out after the optimal solutions are obtained to get the corresponding results, and the two variables of the beam diameter and time are matched during the processing, so as to achieve the maximum improvement of the processing efficiency and the accuracy of the shape trimming. The simulation results show that the controlled time-varying pulsed ion beam reshaping method reduces the residence time by 30 % compared with the conventional ion beam reshaping, the efficiency is 19% higher than that of traditional processing and the facet accuracy reaches 5 nm level.