研究了一种基于二元位相加密的大信息量数字全息水印方法，对需隐藏的水印信息用二元位相编码，然后再用2台阶位相密钥进行加密，作为水印插入宿主图像中，解码后得到了高质量的水印结果1与平面波照明数字全息水印相比，采用位相密钥数字全息水印有效地提高了水印提取的安全性和相对光学效率，并保持了对大信息量水印的提取质量，解码过程不依赖于原图像。计算和分析了二元位相密钥的空间分布对水印信息提取质量的影响，计算结果验证了理论的正确性。

为了实现具有复杂位相结构的二元光束整形元件，提出了采用方光点的激光直写系统来逐点光刻浮雕位相结构的方法，通过双远心投影缩微光路获得5～20μm方点，光点尺寸对应于最小位相单元，从而获得了位相结构的高质量直写1 分析了高斯光点和方光点位相单元结构对二元整形元件衍射效率的影响，方形两台阶二元整形元件的+1级衍射效率达到31%，给出了实验结果。

In the Fresnel condition, the design and optimization method of binary optical element with multi-focus has been investigated. A one-step optimizing algorithm of tilted multi-focus diffractive optical element is 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 four percent, but also the instability of distributing at the different focus,namely difFerent tilted angle,are obviously improved by the modified simulated annealing algorithm(SA). Comparison on one-step and multi-step circle algorithm of optimizing multi-focus diffraction element shows both the faster speed and the higher difFraction efficiency for the one-step algorithm.

In order to realize the fabrication of binary beam shaping element with complex phase structures, a new method of making the relief phase structures under the dot-by-dot exposure mode is presented by using laser direct writing (LDW) system with the square-spot. The size of the square spot obtained with the projection optical configuration is set to match with the minimum phase unit which lead to exposure mode can be easily controlled. The difFraction properties of the phase unit structures etched with single Gaussian spot and square spot are discussed. The binary beam-shaping elements with two-steps by square-spot exposure have been achieved to 31.0% +1 0rder difFraction efficiency. The experimental results are given.