Thermally condensing photons into a coherently split state of light

Abstract

Irreversible splitting of light Prisms and dielectric beam splitters tend to be unitary and reversible optical elements, with the quantum properties of the photons largely irrelevant. Kurtscheid et al. introduce a method of irreversibly, but coherently, populating a split state with photons by thermalizing the photons into a low-energy ground state by repeated absorption-emission interaction with a fluorescent dye within a double-dimple optical cavity. Generation of such a coherent split state could be used as a precursor step to the quasi-continuous creation of many-body entangled states of light, which could be useful in applications in quantum communication, computing, and simulation. Science , this issue p. 894