Experiments towards quantum information with trapped calcium ions

Summary form only given. Ground state cooling and coherent manipulation of ions in a rf-(Paul) trap is the prerequisite for quantum information experiments with trapped ions. In our experiments a single /sup 40/Ca/sup +/ ion in a conventional Paul trap has been cooled to the ground state of vibration with 99.9% (98%) probability in the axial (radial) trap direction. We use a continuous resolved sideband method where we drive the S/sub 1/2/-D/sub 5/2/ quadrupole transition (@ 729nm) and repump the ion to the ground state via the D/sub 5/2/-P/sub 3/2/ dipole transition. Efficient cooling is achieved on the timescale of a few ms.