Effects of coherent coupling of autoionizing states on multiphoton ionization

Authors

N. E. Karapanagioti, Foundation for Research and Technology–Hellas, Institute of Electronic Structure and Laser, 711 10 Heraklion, Crete, Greece
D. Charalambidis, Foundation for Research and Technology–Hellas, Institute of Electronic Structure and Laser, 711 10 Heraklion, Crete, Greece
Cornelis J. Uiterwaal, University of Nebraska - LincolnFollow
C. Fotakis, Foundation for Research and Technology–Hellas, Institute of Electronic Structure and Laser, 711 10 Heraklion, Crete, Greece
H. Bachau, Centre de Physique Theorique MB, CNRS URA 1537, Laboratoire de Collisions Atomiques, Université de Bordeaux I, 351 Cours de Libération, 33405 Talence, France
I. Sanchez, Centre de Physique Theorique MB, CNRS URA 1537, Laboratoire de Collisions Atomiques, Université de Bordeaux I, 351 Cours de Libération, 33405 Talence, France
E. Cormier, Centre de Physique Theorique MB, CNRS URA 1537, Laboratoire de Collisions Atomiques, Université de Bordeaux I, 351 Cours de Libération, 33405 Talence, France

Date of this Version

April 1996

Comments

Published by American Physical Society. Phys. Rev. A 53, 2587 - 2597 (1996). http://link.aps.org/abstract/PRA/v53/p2587. Copyright © 1996 American Physical Society. Permission to use.

Abstract

We present the experimental and theoretical investigation of the effects of the strong electromagnetic coupling of two autoionizing states (AIS’s) on the photoionization properties of an atomic system. These effects are observed by probing the ladder system from the ground state of the atom through a weak two-photon transition to the region of the lower AIS. The experimental observation of the modification of the total ionization and partial photoelectron spectra at different wavelengths of the coupling and probe lasers are accurately reproduced by a theoretical analysis which uses a density-matrix approach. Both theory and experiment indicate a strong inhibition of the ionization of the system in the case when both lasers are resonant with the two atomic transitions, while displaying a rapidly varying asymmetry induced as the detuning between the two states and the fields increases. In the extreme case of a large detuning, two separate structures appear as distinct total ionization and photoelectron peaks. The above findings combined with the full theoretical treatment indicate that the phenomena observed are an experimental demonstration of ac Stark splitting between two AIS’s.