Laser-Phase-Insensitive Coherent Control of Photoion Product States In 2-photon vs. 2-Photon Ionization of Atomic Barium

Abstract

The use of coherent control techniques in atomic and molecular processes offers new possibilities for controlling the outcome of optical interactions, as well as new insights into fundamental interactions between laser fields and atomic and molecular systems. These processes are based on the explicit exploitation of the coherence properties of laser fields and the atomic and molecular interactions they induce. The advances we have witnessed over the past several years have been exciting indeed, and have continued the hope that laser phase might be the key necessary to open new doors of physics, chemistry, and applications based on these principles. Since the expertise of the participants of this workshop is so widely varied, we will start our discussion of coherent control with a brief review of the field and a general introduction to this new class of laser physics. We will include in this introduction a discussion of the fundamental principles of coherent control, and outline some of the experimental difficulties one might expect to encounter when observing coherent control processes in the laboratory. We will then describe in detail a series of investigations we have carried out in which we have observed the strong capability for controlling the photoionization products of atomic barium using the interference between two different two-photon ionization processes. The results we will describe are insenstive to the phase of the laser fields, and therefore offer a great simplification in the experimental techniques required to observe or use this interference.