Quantum interference in laser-assisted photo-ionization excited by a femtosecond x-ray pulse

The photoelectron energy spectra (PESs) excited by monochromaticfemtosecond x-ray pulses in the presence of a femtosecond laser areinvestigated. A PES is composed of a set of separate peaks, showinginteresting comb-like structures. These structures result from thequantum interferences between photoelectron wave packets generatedat different times. The width and the localization of each peak aswell as the number of peaks are determined by all the laser andx-ray parameters. Most of peak heights of the PES are higher thanthe classical predictions.