Metasurfaces can be designed to exhibit different functionalities with incident wavelength, polarization, or angles through appropriate choice and design of the constituent nanostructures. As a proof-of-concept, we design and simulate three multifunctional metalenses with vastly different focal lengths at blue and red wavelengths to show that the wavelength dependence of focal length shift can be engineered to exhibit achromatic, refractive, or diffractive behavior. In addition, we design a metalens capable of achromatically focusing an incident plane wave to a spot and a vortex at red and blue wavelengths, respectively. These metalenses are designed with coupled subwavelength-scale dielectric TiO₂ nanostructures. Our method illustrates a more general design strategy for multifunctional metasurfaces by considering phase and group delay profiles with applications in imaging, spectroscopy, and wearable optical devices.

中文翻译：

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控制多功能超表面的分散

Metasurfaces可以设计通过适当的选择和设计的构成的纳米结构表现出与入射的波长，偏振，或角度不同的功能。作为概念验证，我们设计和模拟了三种在蓝色和红色波长下具有极大不同焦距的多功能金属传感器，以表明可以将焦距偏移的波长依赖性设计为具有消色差，折射或衍射行为。此外，我们设计了一种能够将入射平面波分别消色差地聚焦到红色和蓝色波长处的斑点和涡旋的金属元素。这些metalenses设计为具有耦合的亚波长尺度电介质TiO ₂纳米结构。我们的方法通过考虑相位和群延迟曲线及其在成像，光谱学和可穿戴光学设备中的应用，说明了一种多功能超表面的更通用的设计策略。