倾斜多焦点Fresnel二元光学元件的优化方法

Optimization Methods of Tilted Multi-focus Fresnel Binary Optical Elements

研究了近场Fresnel条件下,具有纵向多焦点的二元光学元件的设计和优化方法。提出在Fresnel衍射近似下,实现了采用倾斜像面多焦点衍射元件的一步优化,得到了衍射光学元件的一般性优化算法。在迭代傅立叶算法的基础上,用改进的迭代傅立叶算法不仅获得更高的衍射效率(提高近3%),同时,明显改善了采用一般迭代傅立叶算法对不同焦点分布(不同倾斜角)下的不稳定性。与分步优化多焦点算法进行了比较,并用MATLAB 编程计算得到所提出的方法,不仅算法速度快,同时衍射效率也更高。

In the Fresnel condition, the design and optimization method of binary optical element with multi-focus has been investigated. An one-step optimizing algorithm of tilted multi-focus diffractive optical element was presented by using a tilted image plane in the Fresnel approximation. Based on iterative Fourier transform algorithm （IFTA）, not only the higher diffraction efficiency （increased about three percents）, but also the instability of distributing at the different focus, namely different tilted angle, were obviously improved by the modified iterative Fourier transform algorithm. Based on MATLAB and worked out by the computer, both the faster speed and the higher diffraction efficiency for the one-step algorithm can be obtained than those for multi-step circle algorithm of optimizing multi-focus diffraction element.