Metasurface provides miniaturized devices for integrated optics. Here, we design and realize a meta-converter to transform a plane-wave beam into multiple Laguerre-Gaussian (LG) modes of different orders at various diffraction angles. The metasurface is fabricated with Au nano-antennas, which vary in length and orientation angle for modulation of both the phase and the amplitude of a scattered wave, on a silica substrate. Our error analysis suggests that the metasurface design is robust over a 400 nm wavelength range. This work presents the manipulation of LG beams through controlling both radial and azimuthal orders, which paves the way in expanding the communication channels by one more dimension (i.e., radial order) and demultiplexing different modes.

中文翻译：

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适用于多种拉盖尔-高斯模式的宽带元转换器

超表面为集成光学提供小型化设备。在这里，我们设计并实现了一个元转换器，将平面波束转换为不同衍射角的不同阶数的多个拉盖尔-高斯 (LG) 模式。超表面是用金纳米天线制造的，其长度和方向角不同，用于在二氧化硅基板上调制散射波的相位和幅度。我们的误差分析表明，超表面设计在 400 nm 波长范围内是稳健的。这项工作提出了通过控制径向和方位角顺序来操纵 LG 波束，这为将通信信道扩展一个维度（即径向顺序）和解复用不同模式铺平了道路。