We report recent progress in our experimental investigation of high-lying Rydberg states of barium in crossed electric and magnetic fields. Through analysis of the nearest-neighbour level spacing statistics, we investigate the evolution of the electron dynamics as the electric field strength is increased.

We report the experimental characterization of axialization -a method of reducing the magnetron motion of a small number of ions stored in a Penning trap. This is an important step in the investigation of the suitability of Penning traps for quantum information processing. The magnetron motion was coupled to the laser-cooled modified cyclotron motion by the application of a nearresonant oscillating quadrupole potential (the "axialization drive"). Measurement of cooling rates of the radial motions of the ions showed an order-of-magnitude increase in the damping rate of the magnetron motion with the axialization drive applied. The experimental results are in good qualitative agreement with a recent theoretical study. In particular, a classical avoided crossing was observed in the motional frequencies as the axialization drive frequency was swept through the optimum value, proving that axialization is indeed a resonant effect.

We demonstrate the efficient modulation of an approximately 100-femtosecond pulse in a Raman medium coherently prepared by nanosecond pulses. Raman sidebands of the ultrashort pulse spanning 360 THz are generated with an efficiency of >5%. We show that the mechanism permitting the sidebands to be generated is the preparation of a significant vibrational coherence in the medium that is robust to disturbance by an intense short pulse. If the observed sidebands were phase compensated, they would form a short train of approximately ten 3-fs pulses. Focusing would permit the realization of a peak intensity of >10(13) W cm(-2).

We report recent experimental developments in the study of high-lying Rydberg states of atomic barium in crossed external electric and magnetic fields. By employing a new, high resolution, pulsed laser system in conjunction with the experimental geometry we have previously used, we have been able to extend our investigations closer to the semiclassical limit. We have compiled Stark maps which clearly indicate changes in dynamics that take place as the electric field strength is increased for a fixed magnetic field strength of 1 T. We comment on these changes and draw comparisons with those observed previously at lower principal quantum number, lower spectral resolution and higher magnetic field strength.

Laser spectroscopy studies are being prepared to measure the 1s ground state hyperfine splitting in trapped cold highly charged ions. The purpose of such experiments is to test quantum electrodynamics in the strong electric field regime. These experiments form part of the HITRAP project at GSI. A brief review of the planned experiments is presented.