Guiding a cold atomic beam along a co-propagating and oblique hollow light guide

We experimentally study the guiding of a low velocity intense source (LVIS) of cold atoms along co-propagating and oblique blue-detuned Laguerre-Gaussian (LG) light beams. For a co-propagating guide we observe a flux enhancement of 120% and we study the effect of guide beam detuning and power. For an oblique LG guide we find few atoms coupled into the guide from the LVIS and primarily observe deflection and recirculation of the LVIS atoms rather than guiding. The guided flux is enhanced by use of an imaged obstruction allowing LVIS atoms to enter the oblique guide more easily. A physical model is presented to account for our observations and highlights important considerations for developing cold atom optic elements based on blue-detuned hollow light beams. (C) 2002 Elsevier Science B.V. All rights reserved.