Rydberg excitation in xenon by the rising edge of a femtosecond laser pulse.

Abstract

Photoelectron spectra in xenon are obtained for (6+1) -photon ionization with intense laser pulses (λ=594 nm, I=5×10 13 W/cm 2 ). By comparing spectra obtained with 300-fs and 600-fs pulses it is shown that the ground state is depleted by nondiabatic passage through high lying Rydberg states (nf) during the rise or the pulse. Spectra are well reproduced by a simple theory including both six-photon excitation to the Rydberg states and one-photon ionization out or these states