title: Steering population flow in coherently driven lossy quantum ladders.
abstract: We present a detailed theory of a technique for the adiabatic control of the population flow through a preselected decaying excited level in a three-level ladder quantum system, as was experimentally demonstrated recently by Garcia-Fernandez et al. [Phys. Rev. Lett. 95, 043001 (2005)]. Specifically, we consider a three-state excitation chain of bound states, 1-2-3, of successively increasing excitation energy, in which probability loss via fluorescence occurs from states 2 and 3. We describe a laser excitation scheme that can, by adjustment of laser parameters, alter at will the relative fraction of population that, starting from state 1, is ultimately lost through states 2 and 3. We present analytical results for the conditions under which quasiadiabatic passage can take place.
authors.affiliation: Institute of Physics, National Academy of Science of Ukraine, Prospect Nauki 46, Kiev-39 03650, Ukraine.
authors.forename: Leonid P
authors.initials: LP
authors.lastname: Yatsenko
authors.forename: Andon A
authors.initials: AA
authors.lastname: Rangelov
authors.forename: Nikolay V
authors.initials: NV
authors.lastname: Vitanov
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Shore