Operation of a “Cold-Atom Laser” in a Magneto-Optical Trap

Hilico, Laurent; Fabre, Claude; Giacobino, E.

doi:10.1209/0295-5075/18/8/004

Cited by 47 publications

(33 citation statements)

References 11 publications

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“…Nevertheless, such a system exhibits most of the features of the proposed superradiant laser, and can be used to test key predictions. While similar lasing has been observed before in a cold-atom system [8], Bohnet et al are the first to characterize the frequency stability of the laser, and to explicitly demonstrate that the laser frequency depends only very weakly on the resonator length. A notable feature of the superradiant laser is that the oscillation is stored predominantly in the atoms, rather than in the light field circulating inside the laser resonator.…”

mentioning

confidence: 52%

An almost lightless laser

Vuletić

2012

Nature

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Lasers are often described in terms of a light field circulating in an optical resonator system. Now a laser has been demonstrated in which the field resides primarily in the atomic medium that is used to generate the light.Atomic clocks that operate on optical transitions in trapped ions or atoms are the most accurate instruments ever made by mankind [1][2][3][4]. In an atomic clock, the quantum mechanical phase between two atomic levels oscillates at a frequency given by the energy difference between those levels. The atom's oscillation is detected by a laser, and today's best clocks are limited by the frequency stability of that readout laser. Recently Murray Holland and colleagues have proposed an ultrastable laser based on an atomic gain medium with a very narrow frequency response [5]. The paper by Bohnet et al. on p. xxx of this issue [6] now reports the first prototype and characterizes key features of such a system. Atomic transitions used for optical clocks have linewidths at the Millihertz level and standard freerunning lasers are not sufficiently stable in frequency to directly interrogate the ultranarrow atomic transition. Rather, the world's best clock lasers are stabilized to a meticulously crafted and controlled reference optical resonator. Currently such reference resonators achieve relative frequency stability below 10 -15 , corresponding to a change in the resonator length by less than the radius of a proton. At this level, the stability of the reference resonator is limited by a fundamental process -thermal noise in the mirrors that leads to fluctuations in the length of the resonator, and thus in the frequency of the laser locked to it. Further progress, though difficult, may be possible by cryogenic operation and use of mirror materials with improved mechanical properties.As an alternative, theorists at Boulder have proposed a laser operating in an unusual parameter regime where the linewidth of the atomic gain medium is much smaller than the linewidth of the laser resonator. In such a system, that may be termed superradiant laser following Dicke's early proposal for a mirrorless laser [7], the laser oscillation is stored predominantly inside the atoms themselves, rather than in the light field circulating inside the resonator. This makes the laser frequency largely immune to cavity length changes (see Fig. 1), with an isolation that is given by the ratio of atomic to resonator linewidths. For their system Bohnet et al. measure an immunity factor exceeding 10 4 .To realize narrow-frequency gain in a medium consisting of rubidium atoms, a species that is easy to laser cool but where no suitable transition is readily available, Bohnet et al. resort to a trick: A narrow atomic line can be mimicked by applying an external laser to weakly drive a transition between two long-lived atomic ground states via a detuned excited state, see Fig. 1c. In this case, the gain profile, and thus the emitted laser light, is not absolutely narrow in frequency, but only when measured relative to the driving lase...

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confidence: 52%

An almost lightless laser

Vuletić

2012

Nature

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“…By pumping near resonance, Mollow gain [8,9] is the dominant process and gives rise to a laser oscillation, whose spectrum is large (of the order of the atomic natural linewidth), whereas by pumping further from resonance, Raman gain between Zeeman sublevels [10] gives rise to a weaker, spectrally sharper laser [11]. At last, by using two counterpropagating pump beams, degenerate four-wave mixing (FWM) [12,13] produces a laser with a power up to 300 W. By adjusting the atom-laser detuning or the pump geometry, we can continuously tune the laser from one regime to another.…”

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confidence: 99%

Mechanisms for Lasing with Cold Atoms as the Gain Medium

2008

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“…100,104 The output polarization is orthogonal to the pump one (contrary to the Mollow laser) and, in our experiment, 100 this gain produces a laser with less power (2 µW). Moreover, the sharpness of the gain curve makes the Raman gain very sensitive to any Doppler shift.…”

Section: Raman Gain Using Zeeman Sublevelsmentioning

confidence: 56%

Cold and Hot Atomic Vapors: A Testbed for Astrophysics?

Baudouin

Guerin

Kaiser

2014

Annual Review of Cold Atoms and Molecules

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Atomic physics experiments, based on hot vapors or laser-cooled atomic samples, may be useful to simulate some astrophysical problems, where radiation pressure, radiative transport or light amplification are involved. We discuss several experiments and proposals, dealing with multiplescattering of light in hot and cold atomic vapors, random lasing in cold atoms and light-induced long-range forces, which may be relevant in this context.

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Operation of a “Cold-Atom Laser” in a Magneto-Optical Trap

Cited by 47 publications

References 11 publications

An almost lightless laser

An almost lightless laser

Mechanisms for Lasing with Cold Atoms as the Gain Medium

Cold and Hot Atomic Vapors: A Testbed for Astrophysics?

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