A time-modulated metasurface integrated with indium-tin-oxide (ITO) can dynamically manipulate the scattered light by imparting dispersionless phase discontinuities with 2π span on wavefronts of the generated sidebands. However, maximal frequency conversion efficiency is restricted to a narrow bandwidth at the vicinity of the resonant wavelength due to the dispersive nature of light–matter interactions in such ITO-integrated metasurfaces. Herein, a multiwavelength time-modulated meta-molecule is numerically investigated, which consists of four metal–insulator–metal meta-atoms that are judiciously designed to support four resonant wavelengths at the near-infrared regime. The metasurface platform allows for application of four sets of independent radio-frequency signals to each meta-molecule, which are optimized to excite the output spectra with dominant first-order up-modulated sidebands. Individual modulation of each meta-atom leads to efficient sideband generation at resonant wavelength corresponding to the biased meta-atom. Nevertheless, the conversion efficiency decays rapidly at off-resonant wavelengths. Concurrent modulation of all four meta-atoms within the meta-molecule configuration offers a pathway to simultaneously generate dominant sidebands at all resonant wavelengths while enhancing the frequency conversion efficiency at inter-resonant wavelengths. As the potential application, beam-steering at the up-modulated sideband by both individually and simultaneously biased meta-atoms is demonstrated. It is revealed that simultaneous modulation enables continuous dynamic light deflection over a broad spectrum spanning on 1–1.8 μm, while the steering angle of the wavelengths changes in the range of 34°–85°. Broadband continuous beam-scanning is a non-trivial task that cannot be accomplished by a quasi-static metasurface relying on dispersive resonant phase shift, which hinders simultaneous implementation of linear phase gradients at all incident wavelengths.

中文翻译：

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在近红外光谱范围内具有时间调制超表面的宽带连续光束控制

与氧化铟锡 (ITO) 集成的时间调制超表面可以通过赋予 2 π 的无色散相位不连续性来动态操纵散射光跨越生成的边带的波前。然而，由于这种 ITO 集成超表面中光-物质相互作用的色散性质，最大频率转换效率被限制在谐振波长附近的窄带宽内。在此，对多波长时间调制超分子进行了数值研究，该超分子由四个金属-绝缘体-金属超原子组成，这些超原子被明智地设计为支持近红外区域的四个谐振波长。超表面平台允许将四组独立的射频信号应用于每个超分子，这些信号经过优化以激发具有主导一阶上调制边带的输出光谱。每个元原子的单独调制导致在对应于偏置元原子的谐振波长处产生有效的边带。然而，转换效率在非谐振波长处迅速衰减。元分子配置中所有四个元原子的同时调制提供了一种途径，可以在所有谐振波长同时产生主要边带，同时提高谐振间波长的频率转换效率。作为潜在的应用，演示了通过单独和同时偏置的元原子在上调制边带上进行波束控制。结果表明，同时调制能够在跨越 1-1.8 的广谱范围内实现连续动态光偏转 元分子配置中所有四个元原子的同时调制提供了一种途径，可以在所有谐振波长同时产生主要边带，同时提高谐振间波长的频率转换效率。作为潜在的应用，演示了通过单独和同时偏置的元原子在上调制边带上进行波束控制。结果表明，同时调制能够在跨越 1-1.8 的广谱范围内实现连续动态光偏转 元分子配置中所有四个元原子的同时调制提供了一种途径，可以在所有谐振波长同时产生主要边带，同时提高谐振间波长的频率转换效率。作为潜在的应用，演示了通过单独和同时偏置的元原子在上调制边带上进行波束控制。结果表明，同时调制能够在跨越 1-1.8 的广谱范围内实现连续动态光偏转 演示了通过单独和同时偏置的元原子在上调制边带上进行波束控制。结果表明，同时调制能够在跨越 1-1.8 的广谱范围内实现连续动态光偏转 演示了通过单独和同时偏置的元原子在上调制边带上进行波束控制。结果表明，同时调制能够在跨越 1-1.8 的广谱范围内实现连续动态光偏转 μ m，而波长的转向角在 34°–85° 范围内变化。宽带连续光束扫描是一项重要的任务，依靠色散共振相移的准静态超表面无法完成，这阻碍了在所有入射波长下同时实现线性相位梯度。