Probing coordinates of Rydberg wave packets - art. no. 021404

We propose a method for determining the time development of the position co ordinates of a Rydberg wave packet using the sudden turn-on of a strong fie ld (a "field step"). The feasibility of the technique is investigated using wave packets created by a half cycle pulse (HCP) that comprise a superposi tion of very-high-lying Rydberg states. The time evolution of the wave pack et is measured using probe pulses that are applied following a variable tim e delay. The probe pulse ionizes a fraction of the atoms and the survival p robability exhibits pronounced oscillations that are associated with the qu asiperiodic evolution of the wave packet. Good agreement is found between t he experimental data and the results of classical trajectory Monte Carlo si mulations. Extraction of classical phase space coordinates from the data is discussed.