Pan Weikang, Wang Zhuo, Chen Yizhen, Li Shiqing, Zheng Xiaoying, Tian Xinzhang, Chen Cong, Xu Nianxi, He Qiong, Zhou Lei, Sun Shulin
Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing, Department of Optical Science and Engineering, School of Information Science and Technology, Fudan University, Shanghai 200433, China.
Yiwu Research Institute of Fudan University, Chengbei Road, Yiwu City, 322000 Zhejiang, China.
Nanophotonics. 2022 Mar 15;11(9):2025-2036. doi: 10.1515/nanoph-2022-0006. eCollection 2022 Apr.
Achieving a pre-designed scattering pattern from an ultra-compact platform is highly desired for on-chip integration optics, but conventional techniques suffer from the limitations of bulky size, wavelength-scale modulation and low efficiency. Here, we propose a new strategy to generate arbitrary scattering far-field patterns from surface-wave (SW) excitations on a designer Pancharatnam-Berry (PB) metasurface. We find that a PB meta-atom serves as a subwavelength scatter to decouple impinging SW to a propagating wave (PW) with tailored amplitude and phase, and thus interference among PWs generated by scatterings at different PB meta-atoms can generate a tailored far-field pattern. As a proof of concept, we design and fabricate a series of PB metasurfaces in the microwave regime and experimentally demonstrate that they can generate desired radiation patterns within a broad frequency band, including unidirectional radiation, line/point focusing, vortex beam and hologram. These findings may stimulate important applications in on-chip integrated photonics.
对于片上集成光学来说，从超紧凑平台实现预先设计的散射图案是非常理想的，但传统技术存在体积庞大、波长尺度调制和效率低等局限性。在这里，我们提出了一种新策略，可从设计的潘查拉特纳姆 - 贝里（PB）超表面上的表面波（SW）激发产生任意散射远场图案。我们发现，一个PB元原子充当亚波长散射体，将入射的表面波解耦为具有定制幅度和相位的传播波（PW），因此由不同PB元原子处的散射产生的传播波之间的干涉可以产生定制的远场图案。作为概念验证，我们在微波频段设计并制造了一系列PB超表面，并通过实验证明它们可以在宽频带内产生所需的辐射图案，包括单向辐射、线/点聚焦、涡旋光束和全息图。这些发现可能会激发片上集成光子学中的重要应用。
