Tunnel Ionization in Strong Fields in atoms and molecules and its applications

Abstract

We look at the theory of ionization of atoms and molecules in the presence of a strong laser field. The history of ionization of atoms is reviewed and the methods used to calculate the ionization rates are examined in detail. In particular the quasi-classical methods used to solve for atomic rates are examined in detail. Early work on the ionization of molecules is also examined. A new method of calculating ionization rates is developed which allows for clear, analytic descriptions of atoms and molecules in intense light fields. The results and implications of this new theory are also examined in both atoms and molecules. The results are compared against known analytic results in the case of atoms and against numerical computation for molecules. Finally, applications of the study of atoms and molecules in intense fields are examined. We show how processes such as high harmonic generation and laser induced electron diffraction occur in strong fields and give an overview of the current state of the art and likely goals for the future. The process of laser induced electron diffraction is given close examination and ways of optimizing the diffraction patterns are discussed. The use of two-color orthogonal fields is shown to greatly increase contrast and efficiency when the carrier phases are tuned correctly.