  We considered the two-photon adiabatic rapid passage excitation of a single
atom from the ground to a Rydberg state. Three schemes were analyzed: both pump
and Stokes fields chirped and pulsed, only the pump field is chirped, and only
the pump field is pulsed and chirped while the Stokes field is continuous wave
(CW). In all three cases high transfer efficiencies $>99\%$ were achieved for
the experimentally realizable Rabi frequencies and the pulse durations of the
fields.
