基于可见光波段的编码优化消色差衍射透镜设计分析

Design and Analysis of Coding Optimized Achromatic Diffraction Lens Based on Visible Band

传统衍射光学元件(DOE)在宽波段工作时存在的严重色散限制了它在宽波段成像中的应用。提出一种基于编码优化的消色差衍射透镜设计,对整个衍射透镜的微结构高度进行编码后,利用粒子群优化算法进行优化,以平衡各个波长在特定焦距下的聚焦作用,使各波长的点扩展函数(PSF)变得几乎相同,实现400~700 nm连续可见光波段中消色差的目的。对传统DOE、分区方式消色差DOE和所提出的编码优化消色差DOE进行仿真验证和成像测试。结果表明,相较于其他两种DOE,编码优化DOE在各波长下的PSF更一致,可见光下截止频率提高至8.6 lp/mm。相较于传统DOE和分区消色差DOE,所提出的编码优化DOE在可见光下具有更好的消色差能力和更高的分辨率。

The serious chromatic dispersion of traditional diffractive optical elements(DOEs) limits their application in wide-band imaging. In this paper, a design of achromatic diffractive lens is proposed. After coding the microstructure height on the whole diffractive lens, the microstructure height is optimized by the particle swarm optimization algorithm to balance the focusing effect of each wavelength in the visible spectrum at a specific focal length, so that the point spread function(PSF) of each wavelength in the visible spectrum becomes almost the same, achieving the goal of achromatism in the continuous visible light band from 400 nm to 700 nm. The simulation and imaging test of traditional DOE, zone achromatic DOE, and coding optimized achromatic DOE proposed in this paper are carried out. Compared with the other two DOEs, the PSF of coding optimized DOE at each wavelength is more consistent, and the cut-off frequency under visible light is increased to 8. 6 lp/mm. Therefore, compared with traditional DOE and zone achromatic DOE, the coding optimized DOE proposed in this paper has better achromatic ability and higher resolution in visible light.