Abstract

We have studied Multi-Photon Ionization (MPI) in Krypton using a field made up of two sub-picosecond laser pulses, one the second harmonic of the other, as a function of phase shift between the two pulses. Recent previous experiments have used either two pulses of incommensurate frequencies, or pulses that were in the "long-pulse" regime¹ where ponderomotive effects dominate the final kinetic energies of ejected photoelectrons. The sub-picosecond pulses of this experiment allow us to identify laser induced resonances during the ionization process² and hence specific ionization pathways. The variation of the total electric field in time and the amplitude of the peak electric field is phase dependent.

© 1992 The Author(s)