Laser-Atom Interactions

The course will focus on theoretical approaches to ionization of atoms and molecules. The strong field approximation, as well as the general theory of adiabatic approximations will be presented. Some of the relevant mathematical tools, such as saddle-point approximation, perturbation theory, and WKB will be explained and applied to derive well-known tunnel ionization formulas. Over the barrier regime will also be analyzed. Reasons for the break-down of standard approximations will be given and alternative methods that take account of Coulomb and other higher-order effects presented. In addition, the role of non-adiabatic effects will be addressed, dealing with the regime where the Keldysh parameter is on the order of or greater than one. Ionization of molecules, where the break-down of standard approximations is particularly relevant, will also be discussed.