Characterization of quasi-one-dimensional Rydberg atoms using multiply directed half-cycle pulses

The characteristics of quasi-one-dimensional (1D) high-n Rydberg atoms produced by photoexciting, in a weak dc field, extreme members of the n=350 Stark manifold are investigated by studying their ionization when subjected to unidirectional electric field pulses, termed half-cycle pulses (HCP's), of duration TpTn where Tn is the classical electron orbital period, directed both parallel and perpendicular to the atomic axis. The observed differences in the ionization characteristics provide a measure of the anisotropy of the momentum distribution. It is shown that HCP's applied transverse to the atomic axis provide a particularly sensitive probe of the quasi-1D nature of the state. The experimental data are in good agreement with the results of classical trajectory Monte Carlo simulations