Generalized Space-Time Engineered Modulation (GSTEM) Metamaterials: A global and extended perspective
Christophe Caloz, Zoé-Lise Deck-Léger, Amir Bahrami, Oscar Céspedes Vicente, Zhiyu Li
Abstract
This article presents a global and extended perspective of electrodynamic metamaterials formed by space and time engineered modulations, which we name generalized space-time engineered modulation (GSTEM) metamaterials, or GSTEMs. This perspective describes metamaterials from a unified <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">spacetime viewpoint</i> and introduces <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">accelerated metamaterials</i> as an extra type of dynamic metamaterials. First, it positions GSTEMs in the even broader context of electrodynamic systems that include (nonmodulated) moving sources in vacuum and moving bodies, explains the difference between the moving-matter nature of the latter and the moving-perturbation nature of GSTEMs, and enumerates the different types of GSTEMs considered, namely space EMs (SEMs), time EMs (TEMs), uniform space-time EMs (USTEMs), and accelerated space-time EMs (ASTEMs). Next, it establishes the physics of the related interfaces, which includes direct-spacetime scattering and inverse-spacetime transition transformations. Then, it exposes the physics of the GSTEMs formed by stacking these interfaces and homogenizing the resulting crystals; this includes an original explanation of light deflection by USTEMs as being a spacetime weighted averaging phenomenon and the demonstration of ASTEM light curving and black hole light attraction. Finally, it discusses some future prospects. Useful complementary information and animations are provided in the downloadable supplementary materials available at <ext-link ext-link-type="uri" xlink:href="http://doi.org/10.1109/MAP.2022.3216773" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">http://doi.org/10.1109/MAP.2022.3216773</ext-link> .