Negative and positive refraction are not Lorentz covariant

TL;DR

This paper investigates how negative and positive refraction, negative phase velocity, and counterposition in moving materials are not invariant under Lorentz transformations, depending on motion speed, incidence angle, and polarization.

Contribution

It demonstrates that negative refraction and related phenomena are not Lorentz covariant, revealing their dependence on observer frame and motion parameters.

Findings

Negative refraction depends on movement speed and wave parameters.

Negative phase velocity and counterposition are not Lorentz covariant.

Refraction phenomena are sensitive to incidence angle and polarization.

Abstract

The refraction of linearly polarized plane waves into a half-space occupied by a material moving at constant velocity was studied by directly implementing the Lorentz transformations of electric and magnetic fields. From the perspective of a co-moving observer, the moving material was a spatially local, pseudochiral omega material. Numerical studies revealed that whether or not negative refraction occurrs in the moving material depends upon the speed of movement as well as the angle of incidence and the polarization state of the incident plane wave. Furthermore, the phenomenons of negative phase velocity and counterposition in the moving material were similarly found not to be Lorentz covariant; both phenomenons were also found to be sensitive to the angle of incidence and the polarization state of the incident plane wave.