Transition radiation in helical metamaterials with strong spatial dispersion

TL;DR

This paper develops a theoretical framework for transition radiation in helical metamaterials with strong spatial dispersion, enabling the reconstruction of plasmon-polariton dispersion laws and predicting unique radiation properties.

Contribution

It introduces a novel effective field theory approach to analyze transition radiation in complex metamaterials with strong spatial dispersion, including a method for dispersion law reconstruction.

Findings

Strong spatial dispersion qualitatively changes transition radiation properties.

Nonzero forward radiation occurs in the paraxial regime due to dispersion effects.

The paper describes Vavilov-Cherenkov radiation and Doppler effects in these metamaterials.

Abstract

The theory of transition radiation in helical metamaterials with strong spatial dispersion is developed in the framework of an effective field theory approach. The average number of photons radiated by a charged particle passing through a plate made of this metamaterial is obtained. Given the positions of the transition radiation maxima in momentum space for different velocities of a charged particle, the method for reconstruction of the dispersion law of plasmon-polaritons in metamaterials is proposed. Applying this method conversely, one can predict the radiation spectrum and polarization properties of transition radiation by means of the dispersion law of plasmon-polaritons in the metamaterial known, for example, from the effective model. It is shown that the strong spatial dispersion alters qualitatively the properties of transition radiation from a charged particle traversing normally a plate made of the helical metamaterial along its symmetry axis in the paraxial regime, viz., there is a nonzero forward radiation in contrast to transition radiation in media without strong spatial dispersion. Vavilov-Cherenkov radiation and the anomalous Doppler effect in helical metamaterials with strong spatial dispersion are described.