Dark-state cooling of atoms in the presence of a uniform external (gravity) field is investigated. The external field leads to a finite lifetime for the dark state and thereby to a lower limit for the temperatures obtainable. The minimum temperature in the presence of a gravity field is found to be ${\mathrm{k}}_{\mathrm{B}}$ ${\mathrm{T}}_{\mathrm{grav}}$ \ensuremath{\sim}Mg\ensuremath{\lambda}/2\ensuremath{\pi} (where M is the atom mass, \ensuremath{\lambda} the wavelength of the cooling laser). This limit is shown to be a universal limit for any laser-cooling scheme.Dark-state cooling of atoms in the presence of a uniform external (gravity) field is investigated. The external field leads to a finite lifetime for the dark state and thereby to a lower limit for the temperatures obtainable. The minimum temperature in the presence of a gravity field is found to be ${\mathrm{k}}_{\mathrm{B}}$${\mathrm{T}}_{\mathrm{grav}}$\ensuremath{\sim}Mg\ensuremath{\lambda}/2\ensuremath{\pi} (where M is the atom mass, \ensuremath{\lambda} the wavelength of the cooling laser). This limit is shown to be a universal limit for any laser-cooling scheme.

Physical Review AFeb 1, 19973 citations

Λ-enhanced grey molasses on the D2 transition of Rubidium-87 atoms

Sara Rosi, A. Burchianti, Stefano Conclave +4 more

Abstract Laser cooling based on dark states, i.e. states decoupled from light, has proven to be effective to increase the phase-space density of cold trapped atoms. Dark-states cooling requires open atomic transitions, in contrast to the ordinary laser cooling used for example in magneto-optical traps (MOTs), which operate on closed atomic transitions. For alkali atoms, dark-states cooling is therefore commonly operated on the D1 transition nS1/2 → nP1/2. We show that, for 87Rb, thanks to the large hyperfine structure separations the use of this transition is not strictly necessary and that “quasi-dark state” cooling is efficient also on the D2 line, 5S1/2 → 5P3/2. We report temperatures as low as (4.0 ± 0.3) μK and an increase of almost an order of magnitude in the phase space density with respect to ordinary laser sub-Doppler cooling.Abstract Laser cooling based on dark states, i.e. states decoupled from light, has proven to be effective to increase the phase-space density of cold trapped atoms. Dark-states cooling requires open atomic transitions, in contrast to the ordinary laser cooling used for example in magneto-optical traps (MOTs), which operate on closed atomic transitions. For alkali atoms, dark-states cooling is therefore commonly operated on the D1 transition nS1/2 → nP1/2. We show that, for 87Rb, thanks to the large hyperfine structure separations the use of this transition is not strictly necessary and that “quasi-dark state” cooling is efficient also on the D2 line, 5S1/2 → 5P3/2. We report temperatures as low as (4.0 ± 0.3) μK and an increase of almost an order of magnitude in the phase space density with respect to ordinary laser sub-Doppler cooling.

arXiv:1709.06467Scientific ReportsJan 16, 201862 citations

A pumped atom laser

Nicholas P. Robins, C. Figl, Matthew Jeppesen +2 more

arXiv:0711.4418Nature PhysicsJul 11, 200886 citations

A Pumped Atom Laser

J. D. Close, Nicholas P. Robins, C. Figl +2 more

Bulletin of the American Physical SocietyMay 29, 20081 citation

{\mathrm{k}}_{\mathrm{B}}

{\mathrm{T}}_{\mathrm{grav}}

\ensuremath{\sim}Mg\ensuremath{\lambda}/2\ensuremath{\pi} (where M is the atom mass, \ensuremath{\lambda} the wavelength of the cooling laser). This limit is shown to be a universal limit for any laser-cooling scheme.