Phase-space views into dye-microcavity thermalised and condensed photons

Abstract

We have observed momentum- and position-resolved spectra and images of the photoluminescence from thermalised and condensed dye-microcavity photons. The spectra yield the dispersion relation and the potential energy landscape for the photons. From this dispersion relation, we find that the effective mass is that of a free photon not a polariton. We place an upper bound on the dimensionless two-dimensional interaction strength of $\tilde{g}\lesssim 10^{-3}$, which is compatible with existing estimates. Both photon-photon and photon-molecule interactions are weak. The temperature is found to be independent of momentum, but dependent on pump spot size, indicating that the system is ergodic but not perfectly at thermal equilibrium. Condensation always happens first in the mode with lowest potential and lowest kinetic energy, although at very high pump powers multimode condensation occurs into other modes.

References in corpus (6)

• Bose-Einstein condensation of photons in an optical microcavity
• Thermalisation of a two-dimensional photonic gas in a 'white-wall' photon box
• Experimental Evidence for Inhomogeneous-Pumping and Energy-Dependent Effects in Photon Bose-Einstein Condensation
• Thermalization and breakdown of thermalization in photon condensates
• A quantum Langevin model for non-equilibrium condensation
• Interaction Effects on Number Fluctuations in a Bose-Einstein Condensate of Light

Cited by in corpus (3)

• First-order spatial coherence measurements in a thermalized two-dimensional photonic quantum gas
• Polarization dynamics in a photon BEC
• The Effective Interaction Strength in a Bose-Einstein Condensate of Photons in a Dye-Filled Microcavity