Abstract

Single-photon ionization, detachment, and dissociation of quantum systems (atoms, molecules, ions, etc.) by rectangular laser pulses are considered. As is well known,¹ sharp features in the continuum (thresholds, autoionization resonances, etc.) are able to modify significantly the dynamics of bound-free transitions in comparison with that predicted by the Fermi golden rule or the pole (Weisskopf-Wigner) approximation. In particular, such strong-coupling phenomena as nonexponential decay and population trapping arise. In this connection the following question can be posed: What are the limits of the pole approximation (PA), beyond which this simple approach should be abandoned in favor of a more exact solution?

© 1998 Optical Society of America