A phonon laser in ultra-cold matter
IPFN and CFIF, Instituto Superior Técnico - 1049-001 Lisboa, Portugal, EU
2 Department of Physics, Umea University - SE-901 87 Umea, Sweden, EU
Accepted: 30 July 2010
We show the possible excitation of a phonon laser instability in an ultra-cold atomic gas confined in a magneto-optical trap. Such an effect results from a negative Landau damping of the collective density perturbations in the gas, leading to the coherent emission of phonons. This laser instability can be driven by a blue-detuned laser superimposed to the usual red-detuning laser beams which usually provide the cooling mechanism. Threshold conditions, instability growth rates and saturation levels are derived. This work generalizes, on theoretical grounds, the recent results obtained with a single-ion phonon laser, to an ultra-cold atomic gas, where real phonons can be excited. Future phonon lasers could thus adequately be called phasers.
PACS: 32.80.Qk – Coherent control of atomic interactions with photons / 37.10.De – Atom cooling methods / 42.55.-f – Lasers
© EPLA, 2010