Physical Review A
Stimulated hyper-Raman adiabatic passage. III. Experiment
K. Böhmer, Thomas Halfmann, Леонід Петрович Яценко, BERNARD SHORE, Klaas Bergmann
Abstract
We report the experimental realization of coherent population transfer from the $2{}^{3}S$ state to $2{}^{3}P$ fine-structure levels of helium, using the technique of hyper-Raman adiabatic passage, in which the pump-laser coupling involves a two-photon transition. We discuss the dependence of population transfer upon pump and Stokes detunings, and show that by suitably setting the detunings one can transfer population efficiently as either a two-step process to final states or as a single-step two-photon transition to an intermediate state. We use an adiabatic-state picture to interpret these experimental results. Since the optimum detuning depends on the pump laser intensity the transfer efficiency is compromised by the variation of the intensity across the spatial profile of the laser beam. Our experimental data agree well with numerical simulation based on density-matrix equations, including all 15 magnetic sublevels.