金刚石复合折射透镜的设计及加工初探

Preliminary study on design and processing of diamond compound refractive lens

复合折射透镜(compound refractive lens,CRL)因具有结构紧凑、焦距可调、准直方便等优点,被用作硬X射线自由电子激光(X-ray free electron laser,XFEL)装置的光束聚焦器件。面向XFEL光束高精度聚焦对高性能CRL的实际需求,从CRL的几何结构设计原理出发,分析了不同材料CRL的性能参数,证明了单晶金刚石材料是适用于XFEL光束聚焦的CRL优选材料。同时,考虑超硬金刚石材料的难加工特性以及低重频钛宝石飞秒激光不能实现大厚度材料高效加工的实际问题,探索了高重频光纤飞秒激光对大厚度单晶金刚石材料进行高效加工的可行性。研究结果表明,高重频飞秒激光精密加工技术是实现金刚石CRL制备的有效手段。

Compound refractive lens(CRL)is used as the X-ray beam focusing device of hard X-ray free electron laser(XFEL)because of its compact structure,tunable focal length and convenient collimation.In order to meet the requirements of XFEL beam focusing with high precision,the performance parameters of CRL made of different materials were analyzed based on the geometric structure design principle of CRL,and it was proved that single crystal diamond material was the preferred material for XFEL beam focusing devices.At the same time,considering the difficulty of the machining characteristics of superhard diamond materials,and the practical problem that low repetition rate and low power titanium sapphire femtosecond laser could not realize efficient machining of large thickness materials,the feasibility of efficient machining of large thickness single crystal diamond materials by high repetition rate and high power fiber femtosecond laser was explored.The research results show that the femtosecond laser precision machining technology with high repetition rate is an effective method to fabricate diamond CRL devices.