Deterministic ion-photon interaction in a cavity

Summary form only given. In a recent experiment, we have investigated the interaction between a single /sup 40/Ca/sup +/-ion stored in a radio-frequency trap and the field of an optical cavity. One mode of the cavity was tuned to the S/sub 1/2/ to P/sub 1/2/ transition of singly ionized calcium at a wavelength of /spl lambda/ = 397 nm. Using laser Doppler cooling in conjunction with the strong confinement of the ion in an effective harmonic potential (frequency 1.1 MHz), the extension of the ion´s wave packet was reduced to 60 nm, corresponding to /spl lambda//7, in the direction of the cavity axis. The position of the ion in the cavity was determined by observing the fluorescent light emitted by the ion after excitation in the cavity field. A large fluorescent rate indicated a position of high intracavity intensity. An image of the standing wave pattern obtained in this way is shown. Note that throughout the measurement the ion remains stationary and the cavity is moved to scan the relative position of ion and field.