Observation of temporal reflection and broadband frequency translation at photonic time interfaces
Observation of temporal reflection and broadband frequency translation at photonic time interfaces
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DOI：
10.1038/s41567-023-01975-y
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发表时间：
2022-08
期刊：
影响因子：
19.6
通讯作者：
Hady Moussa;Gengyu Xu;S. Yin;E. Galiffi;Younes Radi;A. Alú
中科院分区：
文献类型：
--
作者：
Hady Moussa;Gengyu Xu;S. Yin;E. Galiffi;Younes Radi;A. Alú
时间反射是信号的时间演化的均匀反转，其出现在主体材料的性质在空间中均匀地发生突变时。在这样的时间界面处，输入信号的一部分被时间反转，并且由于其动量守恒，其频谱被均匀地平移，从而形成空间界面的时间对应物。时间界面的组合，形成时间超材料和Floquet物质，利用多个时间反射的干涉进行极端波操纵，利用时间作为额外的自由度。在这里，我们报告的观察光子时间反射和相关的宽带频率转换的开关传输线超材料，其有效电容是均匀的，突然改变，通过一个同步的开关阵列。一对时间界面相结合，以证明时间反射引起的波干涉，实现了法布里-珀罗腔的时间对应。我们的研究结果为实现时间超材料和Floquet光子晶体奠定了基础，并为时空中的极端光子操纵提供了机会。
Time reflection is a uniform inversion of the temporal evolution of a signal, which arises when an abrupt change in the properties of the host material occurs uniformly in space. At such a time interface, a portion of the input signal is time reversed, and its frequency spectrum is homogeneously translated as its momentum is conserved, forming the temporal counterpart of a spatial interface. Combinations of time interfaces, forming time metamaterials and Floquet matter, exploit the interference of multiple time reflections for extreme wave manipulation, leveraging time as an additional degree of freedom. Here we report the observation of photonic time reflection and associated broadband frequency translation in a switched transmission-line metamaterial whose effective capacitance is homogeneously and abruptly changed via a synchronized array of switches. A pair of temporal interfaces are combined to demonstrate time-reflection-induced wave interference, realizing the temporal counterpart of a Fabry–Pérot cavity. Our results establish the foundational building blocks to realize time metamaterials and Floquet photonic crystals, with opportunities for extreme photon manipulation in space and time.