Adiabatic focusing of cold atoms in a blue-detuned laser standing wave

Adiabatic focusing of cold atoms in a blue-detuned laser standing wave is a nalyzed. It is shown that using repulsive light forces that push atoms towa rds dark regions and thus minimizes heating, cold atoms can be adiabaticall y compressed by more than an order of magnitude to yield background-free su b-10-nm (rms) spots. The optimal parameters for the atomic lens and the max imal compression ratio ale predicted using an analytic model and found to b e in agreement with the exact results of our Monte Carlo simulations. A com bined adiabatic-coherent scheme is proposed and shown to yield 8.8 nm spot size even for a thermal atomic beam.