Subrecoil Laser Cooling with Adiabatic Transfer

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 [Trec0ex0ex=0ex0ex(k)²/kBM], we cool down to 100 nK (≈1/3Trec) within 1 ms, while almost completely suppressing the diffusive heating of velocity-selective coherent population trapping.