Metasurfaces have outstanding capabilities in manipulating light, enabling functions such as focusing, vortex beam generation, and holography. Such versatile light manipulation, initially studied in free-space optics, has recently been explored in integrated photonics, with light control in waveguides. The ability to achieve multifunctional multiplexing stands is a significant advantage of metasurfaces, and investigating metasurfaces capable of simultaneously accommodating free-space light and guided waves holds the potential to enhance the information capacity and offer extensive application possibilities. However, research in this particular domain is limited, and achieving independent control of these two incident modes without introducing wavelength-dependent degrees of freedom remains a challenging frontier. To solve this problem, we combine the detour phase and resonant phase altogether into on-chip metasurfaces for the first time, which provides extra phase degrees of freedom for independent control of both on-ship and free-space channels. We propose and experimentally demonstrate this novel design with an on-chip multifunctional metasurface that enables the independent control of free-space light and guided waves without the need for introducing additional wavelength-related variables. By controlling the polarization of free-space light and incident direction of guided light, the designed device can achieve a record-high six-channel multifunctional multiplexing hologram and image display.

中文翻译：

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用于导波和自由空间入射下同时光操纵的多功能超表面

超表面在操纵光方面具有出色的能力，可实现聚焦、涡旋光束生成和全息术等功能。这种多功能的光操纵最初是在自由空间光学中研究的，最近在集成光子学中进行了探索，并在波导中进行光控制。实现多功能多路复用站的能力是超表面的一个显着优势，研究能够同时容纳自由空间光和导波的超表面具有增强信息容量并提供广泛应用可能性的潜力。然而，这一特定领域的研究是有限的，在不引入与波长相关的自由度的情况下实现对这两种入射模式的独立控制仍然是一个具有挑战性的前沿领域。为了解决这个问题，我们首次将绕行相位和谐振相位结合到片上超表面中，这为船载通道和自由空间通道的独立控制提供了额外的相位自由度。我们提出并通过实验证明了这种新颖的设计，具有片上多功能超表面，可以独立控制自由空间光和导波，而无需引入额外的波长相关变量。通过控制自由空间光的偏振和引导光的入射方向，所设计的装置可以实现创纪录的六通道多功能复用全息图和图像显示。