As a promising counterpart of two-dimensional metamaterials, metasurfaces enable to arbitrarily control the wavefront of light at subwavelength scale and hold promise for planar holography and applicable multiplexing devices. Nevertheless, the degrees of freedom (DoF) to orthogonally multiplex data have been almost exhausted. Compared with state-of-the-art methods that extensively employ the orthogonal basis such as wavelength, polarization or orbital angular momentum, we propose an unprecedented method of peristrophic multiplexing by combining the spatial frequency orthogonality with the subwavelength detour phase principle. The orthogonal relationship between the spatial frequency of incident light and the locally shifted building blocks of metasurfaces can be regarded as an additional DoF. We experimentally demonstrate the viability of the multiplexed holograms. Moreover, this newly-explored orthogonality is compatible with conventional DoFs. Our findings will contribute to the development of multiplexing metasurfaces and provide a novel solution to nanophotonics, such as large-capacity chip-scale devices and highly integrated communication.

随着航空航天、能源动力和石油化工等领域的快速发展，镍基合金薄板焊接技术成为决定核心零部件使用性能的关键因素之一。镍基合金薄板焊接对热输入敏感，易出现元素偏析、脆性相析出导致焊缝性能降低及产生焊接变形等问题。本文介绍了镍基合金薄板激光焊接技术的研究进展，分别总结了镍基合金薄板的激光自熔焊接和激光填丝焊接两种焊接技术下的焊缝微观组织演变、力学性能和耐腐蚀性能变化以及焊接变形规律，提出了未来研究应重点考虑对焊缝微观组织的预测，并结合先进的算法，提出微观组织、力学性能和耐腐蚀性能的自适应调控策略，进而开发出新型智能化焊接工艺。