Single atoms bound in orbit by single photons

Two recent experiments are discussed which demonstrate real-time trapping a nd monitoring of single atoms within a high-finesse optical resonator. A si ngle atom moving within the resonator generates large variations in the tra nsmission of a weak probe laser, which are recorded in real time. These cav ity QED signals are used to trigger ON a confining potential to trap the at om. In the first experiment, the confining potential is provided by the sin gle-photon forces associated with the cavity QED interaction. An inversion algorithm allows individual atom trajectories to be reconstructed from the record of cavity transmission, and reveals single atoms bound in orbit by t he mechanical forces associated with single photons. In a second experiment , an additional classical standing-wave dipole trap provides the trapping, enabling a 28 ms trap lifetime for single strongly coupled atoms.