For a conventional cascaded metasurface, the combination channel and each single channel are mutually dependent because the phase modulation of a cascaded metasurface is the sum of each single one. Here we propose a cascaded metasurface that can independently encode information into multiple channels. Based on the orientation degeneracy of anisotropic metasurfaces, each single metasurface can produce a quick-response (QR) image in the near field, governed by the Malus law, while the combined channel can produce a holographic image in the far field, governed by geometric phase. The independent and physically separated trichannel design makes information encryption safer.

超表面具有亚波长尺度下精密高效的光波操控能力，但在其单独实现主动式调控方面，目前仍有诸多技术困难亟待克服。液晶与超表面的结合有望发挥各自的长处，实现一种分辨率高、衍射角大、超紧凑的新型主动式光调控器件。以液晶与超表面两部分功能设计的独立与否作为分类依据，回顾了近年来主动式液晶超表面的研究进展，具体包括液晶波片与偏振敏感超表面结合、液晶环境与共振型超表面结合、液晶与超表面光学性质互补等。最后对主动式液晶超表面所面临的挑战以及发展前景进行了讨论和展望。

超构表面是一种具有亚波长特征尺寸的人工平面结构材料，可以在亚波长尺度上对入射电磁波的振幅、相位、偏振、频率、光谱等参量进行精密且灵活的调控，近年来备受关注。振幅是光波的基本参量之一，本文将从振幅调控的角度出发，对基于超构表面材料的振幅调控机理进行分析，主要包括通过改变纳米结构的尺寸和方向角对振幅进行调控，同时对基于振幅调控超构表面的功能器件的研究现状及其应用场景进行总结和讨论。研究表明，振幅调控超构表面具有设计灵活、加工简单、功能强大、可与其他参量调控相融合等特点，其在高分辨率图像显示、高密度信息存储、信息加密、信息复用、光束整形、光信息处理和安全防伪等诸多领域具有重要的研究价值和广阔的应用前景。

计算全息术与纳米印刷术是超表面材料的两种典型应用。近年来，融合全息术与纳米印刷术的多功能超表面成为新兴研究热点，有望在多重光学防伪、信息编码与复用、多通道图像显示、VR/AR等领域得到重要应用。文中在介绍超表面纳米印刷术和计算全息术特点的基础上，将实现两者融合的研究进展进行了详细的归类和特点分析，具体包括：正交偏振复用法、平面合成法、空间堆叠法、光谱+相位调控法、复振幅法、转角简并性法等。最后，对多功能超表面的研究前景进行了展望。

The design of a conventional zoom lens is always challenging because it requires not only sophisticated optical design strategy, but also complex and precise mechanical structures for system adjustment. Here, we propose a continuous-zoom lens consisting of two chiral geometric metasurfaces with dielectric nanobrick arrays sitting on a transparent substrate. The metalens can continuously vary the focal length by rotating either of the two metasurfaces around its optical axis without changing any other conditions. Due to the polarization dependence of the geometric metasurface, the positive and negative polarities are interchangeable in one identical metalens only by changing the handedness of the incident circularly polarized light, which can generate varying focal lengths ranging from ∞ to +∞ in principle.