Variable Potentials for Thermalized Light and Coupled Condensates

TL;DR

This paper introduces a novel method to create variable potentials for thermalized light in a microcavity, enabling the observation of photon Bose-Einstein condensation and interactions, advancing photonic quantum simulation capabilities.

Contribution

The authors demonstrate thermo-optic imprinting to generate variable micropotentials for photons, facilitating thermalization and condensation in a dye-filled microcavity with tunable potential landscapes.

Findings

Observation of photon Bose-Einstein microcondensate in a single microsite

Effective photon-photon interactions via thermo-optic effects

Demonstration of tunnel coupling and eigenstate hybridization in double-well systems

Abstract

For over a decade, cold atoms in lattice potentials have been an attractive platform to simulate phenomena known from solid state theory, as the Mott-insulator transition. In contrast, the field of photonics usually deals with non-equilibrium physics. Recent advances towards photonic simulators of solid state equilibrium effects include polariton double-site and lattice experiments, as well as the demonstration of a photon condensate in a dye-filled microcavity. Here we demonstrate a technique to create variable micropotentials for light using thermo-optic imprinting within an ultrahigh-reflectivity mirror microcavity filled with a dye-polymer solution that is compatible with photon gas thermalization. By repeated absorption-emission cycles photons thermalize to the temperature of the dye solution, and in a single microsite we observe a photon Bose-Einstein microcondensate. Effective interactions between the otherwise nearly non-interacting photons are observed due to thermo-optic effects, and in a double-well system tunnel coupling between sites is demonstrated, as well as the hybridization of eigenstates. Prospects of the new experimental platform include photonic structures in which photons thermalize into entangled manybody states.