Laser cooling and photoionization of alkali atoms

We carry out photoionization experiments on laser-cooled alkali atoms by irradiating rubidium and cesium magneto-opti- cal traps MOTs.with a photoionizing laser beam. Analysis of the loading behavior of the traps allows us to determine photoionization cross-sections for the first excited state of rubidium and cesium based on a trap loadrloss model. In addition, our experimental findings reveal systematic peculiarities, which can be ascribed to the low temperature of the atomic samples under investigation. q2000 Published by Elsevier Science B.V. All rights reserved.