When one extends the conventional stimulated Raman adiabatic passage method
of population transfer; involving a pump pulse preceded by a Stokes pulse,
to situations in which the pump (or pump and Stokes) interaction involves
a two-photon transition, there occur unavoidable dynamic Stark shifts which
prevent maintenance of the relevant resonance conditions. Such shifts can
prevent the desired population transfer. We show, through numerical modelin
g and analytic considerations, that the detrimental effects of dynamic shif
ts can be compensated by a suitable choice of (static) detunings of the car
rier frequencies of the two pulses, so that population transfer can be achi
eved. We present simple analytic expressions for bounding the range of detu
nings for which population transfer can occur, and we present numerical res
ults supporting the simple picture of the two-step linewidth. We illustrate
these remarks by considering specific examples. [S1050-2947(98)09311-1].