Ionization Spectra Induced by Phase-varying Fields

Abstract We consider the effect of a field with time-varying phase on the final-state spectrum produced by ionization of a single ground-state. Although the ground-state population still decays according to the Weisskopf-Wigner formula, the final-state spectrum exhibits a redistribution of population. A single Lorentzian is, in general, no longer obtained and the spectrum may be asymmetric. We concentrate on analytically soluble models with periodic phase-variation, but also briefly consider a random phase and chirp. Finally, the case of two continua is discussed.