Cooperative phase transitions in a system of photons and dye molecules

Abstract

Bose condensed light can form new phases [1] in a dye filled cavity due to the presence of the orientational disorder created by dye molecules which are essentially frozen on the time scale of the photonic thermalization (few ps). At longer times (few ns) molecular degrees of freedom -- orientations and positions -- become important. Including them on equal footing with photons can change the nature of the photonic condensation -- it can proceed as Ist order phase transition which can also result in the mutual phase separation effect -- for photons and dye. The analysis is conducted within the mean field approach in the thermodynamic limit. Recommendations for the experimental detection of the transition nature are formulated.