Digital optical holograms can achieve nanometre-scale resolution as a result of recent advances in metasurface technologies. This has raised hopes for applications in data encryption, data storage, information processing and displays. However, the hologram bandwidth has remained too low for any practical use. To overcome this limitation, information can be stored in the orbital angular momentum of light, as this degree of freedom has an unbounded set of orthogonal helical modes that could function as information channels. Thus far, orbital angular momentum holography has been achieved using phase-only metasurfaces, which, however, are marred by channel crosstalk. As a result, multiplex information from only four channels has been demonstrated. Here, we demonstrate an orbital angular momentum holography technology that is capable of multiplexing up to 200 independent orbital angular momentum channels. This has been achieved by designing a complex-amplitude metasurface in momentum space capable of complete and independent amplitude and phase manipulation. Information was then extracted by Fourier transform using different orbital angular momentum modes of light, allowing lensless reconstruction and holographic videos to be displayed. Our metasurface can be three-dimensionally printed in a polymer matrix on SiO₂ for large-area fabrication.

由于超表面技术的最新进展，数字光学全息图可以实现纳米级分辨率。这为数据加密、数据存储、信息处理和显示方面的应用带来了希望。然而，全息图带宽对于任何实际应用来说仍然太低。为了克服这个限制，信息可以存储在光的轨道角动量中，因为这个自由度有一组无限的正交螺旋模式，可以作为信息通道。到目前为止，轨道角动量全息已经使用仅相位的超表面实现，然而，它受到通道串扰的损害。结果，仅演示了来自四个通道的多路复用信息。这里，我们展示了一种轨道角动量全息技术，该技术能够复用多达 200 个独立的轨道角动量通道。这是通过在动量空间中设计一个复振幅超表面来实现的，该超表面能够进行完整且独立的振幅和相位操作。然后使用光的不同轨道角动量模式通过傅立叶变换提取信息，从而可以显示无透镜重建和全息视频。我们的超表面可以在 SiO 上的聚合物基质中进行三维打印 然后使用光的不同轨道角动量模式通过傅立叶变换提取信息，从而可以显示无透镜重建和全息视频。我们的超表面可以在 SiO 上的聚合物基质中进行三维打印 然后使用光的不同轨道角动量模式通过傅立叶变换提取信息，从而可以显示无透镜重建和全息视频。我们的超表面可以在 SiO 上的聚合物基质中进行三维打印₂大面积加工。