Coherent control of extreme uv absorption and photoemission by the simultaneous irradiation of ultrashort extreme uv and laser pulses

The interaction of a hydrogen atom with the simultaneously applied ultrashort intense laser and xuv pulses was examined by numerically integrating the time-dependent Schrödinger equation. It was found that the atom exhibits a surprisingly rich response. The resonant xuv absorption was suppressed during a very short time of laser irradiation. The latter also induced transitions between excited levels and ionization, which resulted in a jump of the atomic state. The laser-induced photoemission from the atom was significantly affected by the addition of the xuv pulse compared with the case where only the laser field is applied, and its yield depends on the delay between the two pulses.