Laser cooling with velocity-selective coherent population transfer

Norbert Leinfellner, Eugeny Korsunsky

Boris G. Matisov, Eugeny Korsunsky, Vyacheslav M Gordienko +1 more

Rainer Gaggl, Wolfgang Maichen, Rhea C. Holler +2 more

Boris G. Matisov, Vyacheslav M Gordienko, Eugeny Korsunsky +1 more

Tilman Esslinger, F. Sander, Matthias Weidemüller +2 more

We demonstrate subrecoil cooling of rubidium atoms by velocity-selective coherent population trapping. By adiabatic transfer of the cooled atoms into a spin polarized single momentum state we show the coherence of the trapped state. Our cooling scheme takes advantage of the rubidium hyperfine structure to integrate subrecoil and sub-Doppler cooling. Starting from an initial velocity distribution of twice the recoil temperature $[{T}_{\mathrm{rec}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}(\ensuremath{\Elzxh}k{)}^{2}{/k}_{B}M]$, we cool down to 100 nK $(\ensuremath{\approx}\frac{1}{3}{T}_{\mathrm{rec}})$ within 1 ms, while almost completely suppressing the diffusive heating of velocity-selective coherent population trapping.

Eugeny Korsunsky

Velocity-selective adiabatic population transfer by time-delayed laser pulses is considered. In this process only a narrow part of an atomic momentum distribution follows the "dark" state adiabatically. The remaining atoms are excited and partially pumped into the dark state. We show that this effect can be used for cooling atoms below the photon recoil energy using pulsed laser radiation.