Abstract

Obtaining high atomic phase-space densities in optical dipole traps attained much interest lately, and lead to demonstrations of new laser cooling schemes at high densities in red-detuned traps [1], Blue-detuned dipole traps, where repulsive light forces confine atoms mostly in dark, provide weak perturbations of atomic coherences combined with steep potential. This enables observation of much longer coherence times than in comparable red-detuned traps [2], Unfortunately, complexity in forming blue-detuned traps limits their wide use. Hence, one-beam blue-detuned traps are of a great interest because of their possible flexibility in manipulation of the trapping potential size and shape [3], Here, we present a novel configuration of a single-beam blue-detuned dipole trap that is based on a rapidly rotating laser beam. Owing to the simplicity of the trap, large dynamical changes of the potential size and shape were readily obtained. A large initial volume provided an efficient loading into the trap and an adiabatic decrease of the trap size yielded a dramatic increase in the atomic density.

© 1999 Optical Society of America