Nonlinear reversal of PT symmetric phase transition in a system of coupled semiconductor micro-ring resonators

TL;DR

This paper investigates how nonlinear saturation effects in coupled semiconductor micro-ring resonators can reverse the PT-symmetric phase transition, with findings supported by experimental data.

Contribution

It reveals that nonlinear processes can invert the symmetry breaking order in PT-symmetric systems, contrasting with linear predictions.

Findings

Nonlinear saturation effects reverse the PT phase transition.

Non-Hermitian states retain linear eigenvector structure.

Experimental data confirms theoretical predictions.

Abstract

A system of two coupled semiconductor-based resonators is studied when lasing around an exceptional point. We show that the presence of nonlinear saturation effects can have important ramifications on the transition behavior of this system. In sharp contrast with linear PT-symmetric configurations, nonlinear processes are capable of reversing the order in which the symmetry breaking occurs. Yet, even in the nonlinear regime, the resulting non-Hermitian states still retain the structural form of the corresponding linear eigenvectors expected above and below the phase transition point. The conclusions of our analysis are in agreement with experimental data.