振幅自由度对衍射光学元件成像的影响研究

为了在衍射光学元件设计中提高再现像光强分布均匀性,改善成像质量,利用光场传播过程中一定存在泄漏的现象,为目标图像增加了混合型振幅自由度,优化了设计算法,并设计了傅里叶变换型衍射光学元件,验证了方法的有效性.结果表明,增加振幅自由度后设计的元件的再现像光强不均匀性从14%左右降到了1%以下,均方误差从10%左右降到了0.1%以下.该方法对Gerchberg & Saxton(GS)算法和模拟退火算法均适用.

Effect of amplitude freedom on imaging of diffractive optical elements

In order to improve the uniformity of intensity distribution of the reconstructed images and improve the imaging quality in the design of the diffractive optical elements, the design algorithm is optimized by adding a mixed amplitude degree of freedom to the target image due to the fact that there must be leakage in the light field propagation process, and the effectiveness of the method was verified by designing a Fourier transform type diffractive optical element. The simulation results show that, compared without amplitude degree of freedom, the reconstructed image's intensity uniformity of the elements designed by this method is reduced from about 14% to less than 1%, and the mean square error is reduced from about 10% to less than 0.1%, and the method is applicable to both Gerchberg & Saxton(GS) algorithm and simulated annealing algorithm.