Single slow atoms from an atomic fountain observed in a high-finesse optical cavity

A novel setup for investigations in cavity quantum electrodynamics is descr ibed, which combines an optical microcavity (finesse 4.3 x 10(5)) with an a tomic Rb-85 fountain, allowing full control over density and velocity of at oms entering the optical cavity. To demonstrate this point we study the tem poral width of the transmission drops if slow single atoms pass through the cavity. We observe absorptive and dispersive single atom signals in the ca vity transmission in real time. (C) 1999 Elsevier Science B.V. All rights r eserved.