A quasi-continuous superradiant Raman laser with < 1 intracavity photon

Abstract

Abstract. Steady-state collective emission from ensembles of laser cooled atoms has been proposed as a method for generating sub-millihertz linewidth optical lasers, with potential for broad impacts across science and technology. We have built a model system that tests key predictions for such active oscillators using a Raman laser with laser cooled atoms as the gain medium. The laser operates deep in the badcavity, or superradiant, regime of laser physics, where the cavity decay rate is much greater than the atomic coherence decay rate. Specifically, we demonstrate that a system of 10 6 87 Rb atoms trapped in a 1D standing wave optical lattice can spontaneously synchronize and collectively emit a quasi-continuous coherent optical output, even when the intracavity field contains on average < 1 photon.

The development of active optical clock

“…In 2012, JILA group proposed an bad-cavity Raman laser experimental scheme [42,83], which achieved a Raman superradiant laser with an average photon number less than 0.2 in the cavity. Experimentally, the laser operates in deep bad-cavity region, where the ratio of the transverse decoherence rate to cavity decay rate of the laser transition is in the range of 2 × 10 −5 ∼ 10 −3 .…”

Кооперативные Эффекты При Стационарной Генерации Сверхизлучательного Рамановского Лазера

“…В основе работы сверхизлучательного лазера [1] лежит явление кооперативного спонтанного излучения (или сверхизлучения Дике) [2]. В отличие от обычных лазеров, активная среда которых находится в высокодобротном, " хорошем" резонаторе, сверхизлучательный лазер работает в режиме так называемого " плохого" резонатора [3]. В таком режиме фотоны генерируемого света покидают резонатор практически мгновенно, но этого оказывается достаточно для согласования фаз отдельных излучающих атомов друг с другом, что приводит к формированию долгоживущей коллективной когерентности в атомной среде.…”

Steady-state cooperative effects in a continuously generating superradiant Raman laser

“…The operation of a superradiant laser [1] is based on the phenomenon of cooperative spontaneous emission (or the Dicke superradiance) [2]. Unlike conventional lasers, whose active medium is located in a high-quality, " good" cavity, the superradiant laser operates in the regime of the so-called " bad" cavity [3]. In such a regime the photons of the generated light leave the cavity almost instantly, but this turns out to be sufficient to match the phases of individual emitting atoms with each other, which leads to the formation of a long-lived collective coherence in the atomic medium.…”