为提高光学认证技术的安全性及实用性，提出了基于三维空间正交偏振态复用的光学多级安全认证方法。用所设计的多衍射平面多信号窗口相位恢复算法，生成两个相位模板，使由认证图像分割得到的子块图像分布于其三维菲涅耳衍射场的特定位置。一个相位模板作为系统锁，另一个作为认证密钥。用正交偏振光分别照明两相位模板，实现了三维空间衍射场内不同位置强度分布和偏振态分布的控制。只有同时具备认证密钥和三维空间正交偏振态映射密钥，才能恢复认证图像，模拟及实验结果与认证图像的相关系数分别为0.93 和0.79，表明该系统结构紧凑、安全等级高,可以实现分级认证。

To enhance the security level and practicality of optical validation technique, an optical multiple-level security validation method is proposed based on the multiplexing of orthogonal polarization states in threedimensional space. Two phase-only masks are generated by adopting the designed multiple diffractive planes and multiple signal windows phase retrieval algorithm, in order to reproduce Fresnel diffraction field with all of the subblocks which are obtained by the partition of the validated image distributed in specific locations in threedimensional space. One of the two phase-only masks is taken as the system lock. The other one is acted as the security validation key. The two phase-only masks are illuminated by orthogonal polarized respectively. The control of both intensity distributions and polarization distributions in different place are achieved in three-dimensional space. Only when both the security validation key and the three-dimensional orthogonal polarization map key are obtained, the validated image is retrieved. The correlation coefficients between the verification image and simulation or experimental results are 0.93 and 0.79 respectively, which shows the proposed system is a quite compact setup, with both high security level and multiple-level validation functionality.orthogonal polarization multiplexing