Opt Lett. 2023 Feb 15;48(4):956-959. doi: 10.1364/OL.480735.
Anomalous reflection from metasurfaces with 100% efficiency at optical frequencies was not achieved until an all-dielectric quasi-three-dimensional subwavelength structure was proposed. The desired nonlocal control of light waves is realized by designing phase responses of multilayer films at a single wavelength. However, a high-efficiency bandwidth is not controllable by designing only the phase response at a single wavelength. Here, we propose the use of a multilayer metasurface to achieve anomalous reflection with a customized high-efficiency bandwidth. The interference of the successive light waves scattered from the structure at multiple wavelengths is controlled by phase dispersion regulation of multilayer films. As a proof of concept, two sets of multilayer films with different phase dispersions were designed to realize broadband (∼110 nm) and narrowband (∼15 nm) anomalous reflections, both with an efficiency of over 80%. The results offer a general strategy to design high-efficiency anomalous reflection with arbitrary bandwidth and might stimulate various potential applications for metadevices.
直到提出全介质类三维亚波长结构，才在光学频率下实现了 100%效率的异常反射。通过在单个波长下设计多层膜的相位响应，实现了对光波的非局域控制。然而，仅通过设计单个波长的相位响应，无法控制高效率带宽。在这里，我们提出使用多层超表面来实现具有定制高效率带宽的异常反射。通过多层膜的相位色散调节来控制从结构在多个波长处散射的连续光波的干涉。作为概念验证，设计了两组具有不同相位色散的多层膜，以实现宽带（约 110nm）和窄带（约 15nm）异常反射，效率均超过 80%。研究结果为设计任意带宽的高效率异常反射提供了一种通用策略，并可能为超材料器件的各种潜在应用带来启发。
