INTRAPULSE DYNAMICAL EFFECTS IN MULTIPHOTON PROCESSES - THEORETICAL-ANALYSIS

Stationary and nonstationary multilevel models are formulated to analy ze ultrafast multiphoton processes with emphasis on electronic and nuc lear coherence of a near-resonant intermediate state. By identifying a nd characterizing three intrapulse dynamical mechanisms (sequential-re sonance, chirp-following, and time-delay), a clear physical picture is developed for understanding the subtle chirp dependence in intrapulse pump-probe processes. The theoretical analysis in the paper provides not only a possible interpretation for a recent three-photon experimen t but also a general theoretical framework for studying ultrafast mult iphoton processes in atoms and molecules.