一种基于Buchdahl模型的扩束系统设计

A design of beam expansion system based on Buchdahl model

本文基于Buchdahl模型的色散向量分析法设计了一款可用于激光测距的多波长复消色差激光发射镜头,其成本低廉,体积小,光束质量好且能抗高峰值功率激光损伤,设计首先通过Buchdahl色散系数方程计算得到了常用国产高强激光透镜材料的色散向量,然后对光学系统进行光线追迹并计算比例因子,从而进行无焦系统的Buchdahl色散向量计算,最终依据此结果指导优化,优化后的系统在0.707孔径处1064 nm与1572 nm和1550 nm的色差分别仅为2.49×10^(-6) D和4.43×10^(-6) D,1550 nm与1530 nm的色差仅为3.04×10^(-6) D,在波段范围内最大色差仅为4.43×10^(-6) D,最大移焦差仅为0.0005 D,各视场的MTF和点列图完全达到衍射极限,系统的复色差得到有效的矫正,研究结果使Buchdahl模型的色散向量分析法成功应用于工程设计中的无焦光学系统,为无焦光学系统设计提供了一种新思路。

Based on the dispersion vector analysis method of Buchdahl model,this paper designed a multi-wavelength achromatic laser emission lens that can be used for laser ranging,which has low cost,small size,good beam quality and resistance to laser damage at peak power.Firstly,the dispersion vector of commonly used domestic high-intensity laser lens materials was calculated by Buchdahl dispersion coefficient equation.Then,light tracing was performed on the optical system and the scale factor was calculated to calculate the Buchdahl dispersion vector of the non-focal system.Finally,the optimization was guided by this result.The color difference of the optimized system at 0.707 aperture of 1064 nm,1572 nm and 1550 nm was only 2.49×10^(-6) D and 4.43×10^(-6) D,respectively.The color difference between 1550 nm and 1530 nm is only 3.04×10^(-6) D,the maximum color difference in the band range is only 4.43×10^(-6) D,and the maximum shift difference is only 0.0005 D.MTF and dot plot of each field of view fully reach the diffraction limit,and the polychromatic difference of the system is effectively corrected.The research results make the dispersion vector analysis method of Buchdahl model successfully applied to the focus-free optical system in engineering design,and provide a new idea for the design of focus-free optical system.