Dimensional Control of the Coherence Time of Scattered Light in Cold Atom Clouds
Ana Cipris, Mateus a F Biscassi, J C C Capella, Martial Morisse, Hani Naim, Hugo Sedlacek, Apoorav Singh Deo, Stephan Asselie, Robin Kaiser, Raul Celistrino Teixeira, Romain Bachelard, Mathilde Hugbart
公開日: 2025/9/30
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-1D) cloud exhibits systematically longer coherence times than a spherical (3D) 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.