Efficient optical guiding of trapped cold atoms by a hollow laser beam

We present an experimental and theoretical study of efficient optical guiding of trapped cold atoms by a blue-detuned hollow laser beam. We have measured the atomic guiding efficiency with respect to the propagation direction of the hollow beam, which is in good agreement with numerical analysis. In particular, using a copropagating guide laser, we have obtained 20-fold enhancement of atom guiding with a guiding efficiency of 50%. Simulation shows that the efficiency can be increased to 80% with an improved hollow beam mode. The possibility of coherent atom guiding is also discussed