Coherent control of population and pulse propagation beyond the rotating wave approximation
2008 (English)In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 41, no 7, 074016Article in journal (Refereed) Published
The dynamics of populations of the vibrational states in a NO molecule ( one-photon absorption) and of the electronic states in a 4,4'-bis( dimethylamino) stilbene molecule ( two-photon absorption) is studied versus the frequency, intensity and shape of the laser pulse. We show that specially designed infrared laser pulses can build selective populations of certain vibrational states. A detuning of light frequency from the vibrational resonance qualitatively changes the dynamics of populations. It is found out that the populations of the nonresonant levels follow the pulse shape adiabatically if the detuning significantly exceeds the inverse characteristic time of the change of the pulse. Depopulation of the nonresonant vibrational states leads to a high population of the resonant state at the end of the pulse. Complete breakdown of the standard rotating wave approximation for a two-photon absorption process is observed even for a rather small intensity of the laser pulse. An analytical solution for the interaction of a pulse with a three-level system beyond the rotating wave approximation is obtained, and it is in close agreement with the strict numerical solution of the amplitude equations. Special attention is paid to the population dynamics of randomly oriented molecules. The orientational disorder as well as the vibrations limit the coherent population transfer. Calculations show the strong role of the anisotropy of photoexcitation in the coherent control of populations which can affect the anisotropy of photobleaching.
Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2008. Vol. 41, no 7, 074016
self-induced transparency, 2-photon absorption, laser-pulses, basis-sets, density, exchange, behavior, bond
IdentifiersURN: urn:nbn:se:kth:diva-11454DOI: 10.1088/0953-4075/41/7/074016ISI: 000254778700017ScopusID: 2-s2.0-42549157700OAI: oai:DiVA.org:kth-11454DiVA: diva2:276727
QC 201007282009-11-112009-11-112016-07-21Bibliographically approved