Non-equilibrium mode competition in a pumped dye-filled cavity

TL;DR

This paper explores how a pumped dye-filled cavity's steady state and mode occupation are influenced by pump power, cavity lifetime, and dye properties, revealing conditions for lasing or photon condensation.

Contribution

It provides a detailed phase diagram analysis of mode competition in a dye-filled cavity, highlighting the role of mode repulsion in different regimes.

Findings

Identification of conditions leading to multi-mode lasing or photon condensation

Role of mode repulsion in weak cavity loss regimes

Dependence of steady state on pump power and cavity parameters

Abstract

We consider a homogeneously pumped photon gas coupled to a dye medium and investigate how its steady state is effected when varying the pump power, the photon cavity lifetime and the cutoff frequency. We study how the interplay between pumping, loss, and dye-induced thermalization influences the selection of the cavity modes that acquire large occupation. Depending on the parameter regime, the latter can be related either to lasing of (typically multiple) modes or to equilibrium-like photon condensation in the ground mode. We calculate and explain the phase diagram of the system, with a particular emphasis on the role played by a mode repulsion that occurs in the regime of weak cavity loss.