Observation of Radially Localized Atomic Electron Wave Packets

Abstract

We have observed a radially localized electron wave packet in a direct pump-probe experiment with 6-ps laser pulses. Use is made of the fact that both excitation and ionization take place predominantly close to the atomic core. A wave packet is created by coherently exciting Rydberg states of rubidium atoms around $n=41\mathrm{}$ with a pump pulse, and detected through ionization with a delayed probe pulse. The wave packet is observed to return to the core twice before the spreading becomes too large.