Wave Instabilities and Unidirectional Light Flow in a Cavity with Rotating Walls

TL;DR

This paper explores how rotating cavity walls can induce wave instabilities and unidirectional light flow, revealing conditions for electromagnetic field growth and potential for optical isolation.

Contribution

It demonstrates the emergence of wave instabilities in a rotating cavity and proposes mechanisms for asymmetric light flow and optical isolation based on wall motion.

Findings

Wave instabilities occur at high angular velocities with small vacuum gaps.

Certain oscillation modes exhibit exponential electromagnetic growth.

Asymmetric light flow and optical isolation are achievable through wall rotation.

Abstract

We investigate the conditions for the emergence of wave instabilities in a vacuum cavity delimited by cylindrical metallic walls under rotation. It is shown that for a small vacuum gap and for an angular velocity exceeding a certain threshold, the interactions between the surface plasmon polaritons supported by each wall give rise to an unstable behavior of the electromagnetic field manifested in an exponential growth with time. The instabilities occur only for certain modes of oscillation and are due to the transformation of kinetic energy into electromagnetic energy. We also study the possibility of having asymmetric light flows and optical isolation relying on the relative motion of the cavity walls.