title: On the relative roles of higher-order nonlinearity and ionization in ultrafast light-matter interactions.
abstract: Far off-resonant ultrafast and nonlinear light-matter interactions are studied using a one-dimensional atomic model. Results from a pump-probe diagnostic reveal that any higher-order nonlinear refraction is masked by ionization-induced defocusing before it becomes significant. On the other hand, we show that signatures of a higher-order nonlinearity may still be manifest via low-order harmonics of the pump center frequency. Implications for filamentation of femtosecond pulses are pointed out.
authors.affiliation: College of Optical Sciences, University of Arizona, Tucson, Arizona 85721, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Brown
authors.forename: E M
authors.initials: EM
authors.lastname: Wright
authors.forename: J V
authors.initials: JV
authors.lastname: Moloney
authors.forename: M
authors.initials: M
authors.lastname: Kolesik