Using techniques of ultrafast coherent control, we propose a method to produce high-purity high-
l (angular momentum) states in Rydberg Stark wave packets. Two time-delayed phase-locked laser pulses excite the atom from a low-lying ``launch state'' into a low-
l Rydberg wave packet, in the presence of a static electric field. By choosing the time delays between the pulses, and the static electric field, we find that a high-
l state with high purity can be created at the target time.
Ultrashort, nearly unipolar electric field pulses are used to produce novel dynamic states in Rydberg atoms. A single 500 fsec field pulse redistributes essentially all of the population from a single stationary Rydberg state to hundreds of different final states. The dynamic evolution of the nonstationary wave packet is monitored using a second, time-delayed pulse. The time-dependent momentum-space probability distribution of the wave packet can be retrieved experimentally using a classical impulse approximation.
Atomic wave packets are produced in strong magnetic fields by exciting rubidium atoms with a short UV laser pulse. The strength of the magnetic field is varied from 0 to 3.3 T. In a classical model of these Rydberg atoms, this variation leads to a progression of the system from a regime of regular motion to one where chaotic motion dominates. The evolution of the wave packet is observed using a phase-sensitive technique and is compared to the predictions of a semiclassical model. The effect of an electric field, applied parallel to the magentic field, is also studied. As the electric field is increased, significant changes occur that are due in part to the appearance of new orbits.