Dimensional control of the coherence time of scattered light in cold atom clouds
Phys. Rev. A 113, 022208 – Published 10 February, 2026
DOI: https://doi.org/10.1103/x27v-k5kl
Abstract
Cold atomic clouds are promising platforms for generating correlated photons, but multiple scattering and associated Doppler broadening limit their temporal coherence. Here we demonstrate that cloud geometry provides a powerful means to extend the coherence time of scattered light. In the experiment, intensity-correlation measurements show that an elongated (quasi-one-dimensional) cloud exhibits systematically longer coherence times than a spherical (three-dimensional) cloud of the same on-axis optical thickness, as a direct consequence of the suppression of multiple scattering in the elongated geometry. Random-walk simulations reproduce this trend and further show that elongation drives the coherence time toward the single-scattering limit. The combined results establish cloud geometry as a robust control parameter for temporal coherence in cold atom ensembles, with potential applications in quantum optics and communication.
