Efficient population transfer in a three-level ladder system by frequency-swept ultrashort laser pulses

Abstract

Enhanced population transfer from the lowest to the highest level in the three-state ladder 5s\ensuremath{\rightarrow}5p\ensuremath{\rightarrow}5d of the rubidium atom by frequency-swept ultrashort laser pulses is observed if the frequency sweep first makes the pulse resonant with the 5s\ensuremath{\rightarrow}5p transition, and later with the 5p\ensuremath{\rightarrow}5d transition. With this ``intuitive'' scheme it is possible to achive complete population inversion via the intermediate level by two successive adiabatic passages. Complete inversion is also obtained by a ``counterintuitive'' direction of the frequency sweep, in which case population of the intermediate level during the pulse is strongly reduced.