Freedhoff, Helen

Helen Freedhoff

Full Professor
Retired
Ph.D. (Toronto)
hsf@yorku.ca

Department(s): Physics and Astronomy

Office:
Phone: ext.

Research Fields
Atomic, Molecular and Optical Physics

Research Types
Theoretical


Research specialization
Theory of interactions between matter and radiation, with emphasis on multi-level, multi-atom, and multi-photon processes.


The objectives of my research program are to further the basic understanding of the interaction of radiation with matter, with emphasis on multi-level, multi-atom, and multi-photon processes. In general, we develop a theory to describe (new) physical phenomena in strongly-coupled light-plus-atom systems. One of the problems we address is Cooperative Atomic Effects. When two or more atoms interact cooperatively with a common radiation field, frequency shifts and altered rates and angular distributions of radiation result (superradiance). These phenomena have received greatly increased experimental attention in recent years with the cooling and trapping of atoms and ions in precise geometric configurations with separations of order λ. We study cooperative radiation processes by atomic arrays in 1-, 2-, and 3-dimensions, involving both one- and two-photon transitions.

Another problem we study is Intense Field Resonance Fluorescence.  Our recent work in this area has involved a study of the dynamic Stark effect of atoms in bichromatic and trichromatic driving fields. We also study Two-Photon Transitions by extending the methods that have been developed over the past 20 years for the study of one-photon processes.