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arXiv:2007.07798 · Optics Letters

Coherence time of a cold-atom laser below threshold

Graeme Harvie, Adam Butcher, Jon Goldwin

Published Aug 28, 2020• 2 citations
arXivHTMLPDF

Abstract

We experimentally study the coherence time of a below-threshold Raman laser in which the gain medium is a gas of magneto-optically trapped atoms. The second-order optical coherence exhibits photon bunching with a correlation time that is varied by two orders of magnitude by controlling the gain. Results are in good agreement with a simple analytic model that suggests the effect is dominated by gain, rather than dispersion, in this system. Cavity ring-down measurements show the photon lifetime, related to the first-order coherence time, is also increased.

DOI
10.1364/ol.402975

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We experimentally study the coherence time of a below-threshold Raman laser in which the gain medium is a gas of magneto-optically trapped atoms. The second-order optical coherence exhibits photon bunching with a correlation time that is varied by two orders of magnitude by controlling the gain. Results are in good agreement with a simple analytic model that suggests the effect is dominated by gain, rather than dispersion, in this system. Cavity ring-down measurements show the photon lifetime, related to the first-order coherence time, is also increased.
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