Metasurfaces constitute an emerging technology, allowing for compact manipulation of all degrees of freedom of an incident lightwave. A key ongoing challenge in the design of these structures is how to allow for energy-efficient dynamic (active) operation, particularly for the polarization of incident light, which other standard devices typically cannot efficiently act upon. Here, we present a quasi-two-dimensional magneto-optic metasurface capable of simultaneously high-contrast on/off operation, as well as rotation of the polarization angle of a linearly polarized wave—that is, without converting the incident linear polarization to elliptical, which is normally particularly challenging. Furthermore, the device’s operation is broadband, with a bandwidth of around 5 µm, and can be conveniently manipulated using an external magnetic bias. Our findings, corroborated using two different full-wave simulation approaches, may allow for functional metasurfaces operating in the terahertz (THz) regime, giving rise to robust, energy-efficient, and high-dynamic-range broadband isolation, to be used for a wealth of optoelectronic and communication applications.

中文翻译：

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用于紧凑隔离的有源太赫兹超表面

超表面构成了一项新兴技术，允许对入射光波的所有自由度进行紧凑操作。这些结构设计中一个关键的持续挑战是如何允许节能动态（主动）操作，特别是对于入射光的偏振，其他标准设备通常无法有效地作用。在这里，我们提出了一种准二维磁光超表面，能够同时进行高对比度开/关操作，以及线偏振波的偏振角旋转——也就是说，无需将入射线偏振转换为椭圆，这通常特别具有挑战性。此外，该设备的操作是宽带的，带宽约为 5 µm，可以使用外部磁偏置方便地进行操作。