Date of Award

Spring 1-1-2017

Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Andreas Becker

Second Advisor

Agnieszka Jaron-Becker

Third Advisor

David Jonas

Fourth Advisor

Margaret Murnane

Fifth Advisor

Jose D’incao


Perturbative nonlinear optics consists of many powerful predictive theoretical methods, in- cluding the perturbative series of observables related to the interaction of light with matter. The light intensity limits of such series have been studied in the past for highly nonlinear processes such as above threshold ionization and high harmonic generation. A more recent debate focuses on the limits of applicability of perturbation theory for the nonlinear electrical susceptibility and the nonlinear index of refraction of atoms, which are important parameters to study, for example, for filamentation of laser pulses in nonlinear media.

In this thesis we analyze theoretical predictions for the electrical susceptibility of atoms for the transition from the perturbative to the nonperturbative intensity regime. To this end, we apply a numerical basis state method that allows us to perform respective calculations in the framework of perturbation theory as well as using ab-initio methods. The results let us identify the intensity at which the application of perturbation theory breaks down. Furthermore, we provide an analysis of the nonlinear susceptibility as a function of time during the interaction with the laser pulse and find that theoretical predictions are in good agreement with recent experimental data.