Journal of Modern Optics
An Extended Model of Double Optical Resonance
Antoni Wójcik, R. Parzyński
Abstract
A ladder-type model of double optical resonance, extended by allowing some internal structure for the middle level, is considered and its classical analogue is given. Ionization and photoelectron energy spectra from such a model with singlet, doublet and triplet middle-level structures are evaluated numerically for a wide range of laser pulse intensities and durations. The topics of most interest are peak narrowing by extremely strong upper-level ionization damping, reversal of the peak-height asymmetry by increasing lower-resonance strength at non-zero upper-resonance detuning, and number-of-peak reduction and flattening of the spectrum by shortening of the atom-photon interaction time. When applied to natural barium, this model gives results in good agreement with experiment.