Stationary Charge Radiation in Anisotropic Photonic Time Crystals

TL;DR

This paper investigates how anisotropic photonic time crystals can induce stationary charges to emit radiation, with the radiation pattern governed by the band structure, expanding the potential applications of time metamaterials.

Contribution

It introduces a novel analysis of anisotropic photonic time crystals, demonstrating their ability to generate and control radiation from stationary charges, unlike isotropic counterparts.

Findings

Stationary charges in APTCs emit radiation.

Radiation distribution is controlled by the band structure.

The approach extends functionalities of time metamaterials.

Abstract

Time metamaterials exhibit a great potential for wave manipulation, drawing increasing attention in recent years. Here, we explore the exotic wave dynamics in an anisotropic photonic time crystal (APTC), formed by an anisotropic medium whose optical properties are uniformly and periodically changed in time. Based on a temporal transfer matrix formalism, we show that a stationary charge embedded in an APTC can emit radiation, in contrast to the case of an isotropic photonic time crystal, and its distribution in momentum space is controlled by the APTC band structure. Our approach extends the functionalities of time metamaterials, offering new opportunities for simultaneous radiation generation and control, with implications for both classical and quantum applications.