Are photon momenta in left-handed materials reversed?

TL;DR

This paper develops a semiclassical theory to analyze photon momenta in left-handed materials, revealing that linear momentum reverses direction while orbital and spin angular momenta do not, offering new insights into LHMs' fundamental properties.

Contribution

The paper introduces a semiclassical framework and uses a two-level atom probe to show the reversal of photon linear momentum in LHMs, while orbital and spin angular momenta remain unchanged.

Findings

Photon linear momentum reverses in LHMs

Orbital angular momentum remains unreversed

Spin angular momentum remains unreversed

Abstract

We develop a semiclassical theory to describe the photon momenta in left-handed materials (LHMs). A single two-level atom is introduced as an "explorer" to probe the momenta of photons. We demonstrate that the linear momentum of the photons reverses its direction in LHMs. However the orbital angular momentum is remains unreversed, although the wave-fronts reversed their screwing fashion. We theoretically predict that the spin angular momentum is also unreversed. The investigation of photon momenta will provide insights into the fundamental properties of LHMs.