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Advances in Physical Chemistry
Volume 2010 (2010), Article ID 798419, 8 pages
http://dx.doi.org/10.1155/2010/798419
Research Article

Stimulated Raman Adiabatic Passage in a Dense Medium

1Faculty of Sciences, Holon Institute of Technology, 52 Golomb Steet, Holon 58102, Israel
2Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel-Aviv University, Tel Aviv 69978, Israel

Received 11 September 2010; Accepted 23 October 2010

Academic Editor: Kenneth Ruud

Copyright © 2010 B. D. Fainberg and B. Levinsky. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We have considered a coherent population transfer to a higher excited singlet state () of molecules with anomalous fluorescence in molecular assemblies (e.g., a dense medium). A direct excitation to requires light in the UV region. Because of this, the transition is conveniently realized by a two-step (two-photon) process: , where transitions and correspond to the optical region. We have shown that efficient stimulated Raman adiabatic passage (STIRAP) in the ladder configuration can be realized in this case, using suitably chirped pulses, to compensate a change of the two-photon transition frequency in time, induced by the pulses themselves, due to near dipole-dipole interactions. We have provided a reduced state formulation of the optical control process. Chirping the “pump” pulse that excites transition is nonequivalent to chirping the “Stokes” pulse that excites transition , with respect to the population of the intermediate state () in the pulse nonadiabatic regime. We have also shown that with suitably chirped pulses, efficient STIRAP still persists even for a rather large decay of the intermediate state.