Actively tunable petal-shaped pattern emissions have been successfully demonstrated by the cascade of two innovative rotational vortex metasurface arrays (RVMAs). To ensure accurate cascade, each RVMA comprises a central unit with the capability to converge light, surrounded by six units designed for emitting converging vortex beams (VBs) and converging perfect vortex beams (PVBs) with topological numbers (TCs) of 3, 6, and 9, respectively. Notably, although the number of spiral branches and the diameters of the VB and PVB are determined in accordance with specific design TCs, the diameters and the number of petals for the petal-shaped beam emissions are actively adjusted through the rotation of the RVMAs. Interestingly, the superimposition of these VBs, PVBs, or both, consistently generates petal-shaped beams with various petal numbers and diameters, highlighting the remarkable versatility of the approach. To demonstrate the proposed concept across wavelengths, indicating its broadband operation capability, RVMA performance in the visible spectrum is thoroughly investigated, ranging from 450 to 600 nm. The tunability of the cascade of RVMAs for petal-shaped emissions featuring diverse diameters and petal numbers has been validated at visible wavelengths, affirming the broad capabilities of the concept presented in this study.

中文翻译：

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旋转涡旋超表面阵列实现可调谐完美花瓣形光束发射


两个创新的旋转涡旋超表面阵列（RVMA）的级联已成功证明了主动可调的花瓣形图案发射。为了确保精确的级联，每个 RVMA 都包含一个具有会聚光能力的中央单元，周围有六个单元，设计用于发射会聚涡旋光束 (VB) 和会聚完美涡旋光束 (PVB)，拓扑数 (TC) 为 3、6、和 9 分别。值得注意的是，虽然螺旋分支的数量以及VB和PVB的直径是根据具体设计的TC确定的，但花瓣形光束发射的花瓣的直径和数量是通过RVMA的旋转来主动调节的。有趣的是，这些 VB、PVB 或两者的叠加，一致地生成具有不同花瓣数量和直径的花瓣形光束，凸显了该方法的卓越多功能性。为了跨波长展示所提出的概念，表明其宽带操作能力，对 450 至 600 nm 可见光谱中的 RVMA 性能进行了彻底研究。具有不同直径和花瓣数量的花瓣形发射的 RVMA 级联的可调性已在可见波长下得到验证，证实了本研究中提出的概念的广泛功能。