Exceptional points and photonic catastrophe

TL;DR

This paper demonstrates that exceptional points in coupled optical structures cause a global collapse of eigenfunctions, leading to highly sensitive light propagation phenomena similar to classical and quantum catastrophes.

Contribution

It reveals the occurrence of exceptional points in spatially-extended optical systems with balanced gain and loss, and explores their impact on light behavior and catastrophe-like effects.

Findings

Global collapse at EP alters light propagation dramatically.

Light becomes highly sensitive to initial conditions near EP.

Illustrations include beam diffraction and Bloch oscillation catastrophes.

Abstract

Exceptional points (EPs) with a global collapse of pairs of eigenfunctions are shown to arise in two locally-coupled and spatially-extended optical structures with balanced gain and loss. Global collapse at the EP deeply changes light propagation, which becomes very sensitive to small changes of initial conditions or system parameters, similarly to what happens in models of classical or quantum catastrophes. The implications of global collapse for light behavior are illustrated by considering discrete beam diffraction and Bloch oscillation catastrophe in coupled waveguide lattices.