This article presents a novel class of (space–)time-modulated metasurfaces, namely, (space–)time metasurfaces that are modulated by pseudorandom sequence (PRS) waveforms. In contrast to their harmonically or quasi-harmonically modulated counterparts, these metasurfaces massively alter the temporal spectrum of the waves that they process; as a result, they exhibit distinct properties and offer complementary applications. These metasurfaces are assumed, here, to operate in the “slow-modulation” regime, where the fixed-state time between the state transition is much larger than the transient time associated with the dispersion of the media involved, which allows for the safe separation of the time-variance and frequency-dispersive effects of the system.

中文翻译：

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伪随机序列（空间-）时间调制超表面：原理、操作和应用

本文介绍了一类新颖的（空间-）时间调制超表面，即由伪随机序列（PRS）波形调制的（空间-）时间超表面。与它们的谐波或准谐波调制对应物相比，这些超表面极大地改变了它们处理的波的时间谱。因此，它们表现出独特的特性并提供互补的应用。这里假设这些超表面在“慢调制”状态下运行，其中状态转换之间的固定状态时间远大于与所涉及的介质分散相关的瞬态时间，这允许安全分离系统的时变和频散效应。