Bose-Einstein condensation of photons with nonlocal nonlinearity in a dye-doped graded-index microcavity

TL;DR

This paper investigates Bose-Einstein condensation of photons in a dye-doped graded-index microcavity, emphasizing the effects of nonlocal nonlinearity and comparing theoretical results with experimental data.

Contribution

It introduces a model incorporating nonlocal nonlinear effects in photon BEC within a graded-index microcavity, extending previous work by including thermal lensing and nonlinear interactions.

Findings

Photon gas behaves as a 2D Bose gas in a harmonic trap

Nonlocal nonlinearity influences the condensation process

Results align quantitatively with experimental observations

Abstract

We consider a microcavity made by a graded-index (GRIN) glass, doped by dye molecules, placed within two planar mirrors and study Bose-Einstein condensation (BEC) of photons. The presence of the mirrors leads to an effective photon mass, and the index grading provides an effective trapping frequency; the photon gas becomes formally equivalent to a two dimensional Bose gas trapped in an isotropic harmonic potential. The inclusion of nonlinear effects provides an effective interaction between photons. We discuss, in particular, thermal lensing effects and nonlocal nonlinearity, and quantitatively compare our results with the reported experimental data.