Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States.
Department of Mechanical Engineering, Stanford University, Stanford, California 94305, United States.
Nano Lett. 2020 Jul 8;20(7):5127-5132. doi: 10.1021/acs.nanolett.0c01359. Epub 2020 Jun 23.
Metasurface lenses provide an ultrathin platform in which to focus light, but weak light-matter interactions limit their dynamic tunability. Here we design submicron-thick, ultrahigh quality factor (high-) metalenses that enable dynamic modulation of the focal length and intensity. Using full-field simulations, we show that quality factors exceeding 5000 can be generated by including subtle, periodic perturbations within the constituent Si nanoantennas. Such high- resonances enable lens modulation based on the nonlinear Kerr effect, with focal lengths varying from 4 to 6.5 μm and focal intensities decreasing by half as input intensity increases from 0.1 to 1 mW/μm. We also show how multiple high- resonances can be embedded in the lens response through judicious placement of the perturbations. Our high- lens design, with quality factors 2 orders of magnitude higher than existing lens designs, provides a foundation for reconfigurable, multiplexed, and hyperspectral metasurface imaging platforms.
超表面透镜为聚焦光提供了一个超薄的平台，但弱光物质相互作用限制了其动态可调谐性。在这里，我们设计了亚微米厚度、超高品质因数（高）金属透镜，实现了焦距和强度的动态调制。通过全场模拟，我们表明，通过在组成的 Si 纳米天线中包含微妙的、周期性的微扰，可以产生超过 5000 的品质因数。这种高共振使基于非线性克尔效应的透镜调制成为可能，焦距从 4 到 6.5 μm 变化，而焦点强度随着输入强度从 0.1 到 1 mW/μm 的增加而降低一半。我们还展示了如何通过巧妙地放置微扰将多个高共振嵌入透镜响应中。我们的高 Q 因子透镜设计，其品质因数比现有透镜设计高 2 个数量级，为可重构、复用和超光谱超表面成像平台提供了基础。
