Uiterwaal, Cornelis J.; Fotakis, C.; Bachau, H.; Sanchez, I.; and Cormier, E., "Effects of coherent coupling of autoionizing states on multiphoton ionization" (1996) Phys. Rev. A 53, 2587Rev. A 53, -2597Rev. A 53, (1996 [ 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. We present the experimental and theoretical investigation of the effects of the strong electromagnetic coupling of two autoionizing states ͑AIS's͒ 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..
We describe a novel experiment on Rydberg atoms in crossed electric and magnetic fields, recently performed at Imperial College. The novelty resides in a combination of a crossed-field geometry with a time-gated detection technique, by which separation of the circularly polarized components is now achieved. The importance of achieving such a separation and the new opportunities it opens up are explained. By this approach, a map of the diamagnetic Stark patterns is obtained. The data exhibit interesting behaviour in that the hydrogenic and non-hydrogenic groups within the n-shell now become distinguishable. Their evolution as a function of field strength brings out the difference between linear and quadratic effects. The levels with a quadratic dependence on electric field strength eventually invade and dominate the spectrum. We surmise that the trend from order to chaos is different in crossed fields from the trend in the diamagnetic limit. We comment on further theory required to clarify this point. Our observations extend up to and slightly above the saddle-point energy.
The even parity 4pnp J"0, 1, 2 doubly excited autoionizing states of neutral calcium in an atomic beam are investigated by a two-step isolated core excitation (ICE) method using two different combinations of polarization of the laser beams. The different excited energy levels are assigned to nine autoionizing Rydberg series 4pnp J"0, 1, 2 for 84n422. The theoretical interpretation is achieved by a combination of the eigenchannel R-matrix theory and the multichannel quantum defect (MQDT) method. Two, five and six closed interacting channels are introduced for the J"0, J"1 and J"2 series respectively. Theoretical energy level positions, autoionization widths and excitation profiles are compared with the experimental data, confirming the identification of the observed structures and providing evidence of extended mixing between the 4p np and 4p np series.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.