We show that switching of excited state populations can be controlled by employing the Ramsey-type interference due to the Autler-Townes effect. Fringes in the Autler-Townes spectra have first been reported in , where a closed three-level system was coupled by a resonant pulsed pump laser field in the first excitation step and created time-varying dressed states, which were probed by a simultaneous probe pulse. In our experiment, a supersonic sodium beam is crossed by two cw laser beams. A strong and short (tightly focused) pump laser field pulse couples the lower and the intermediate level, and weak and long (less tightly focused) probe laser field pulse couples the intermediate and the upper level. The pump laser thus creates two spatially varying dressed states, whose energies depend on the detuning and Rabi frequency of the pump field. Our numerical calculations show that such an arrangement can be used to control the spatial distribution (or time dependence) of populations of highly excited atomic or molecular states. When the frequencies of both laser fields are fixed, the excitation of the upper level can take place at two distinct spatial locations, at which the probe laser field is resonant with one of the dressed states created by the pump field. This leads to two alternative excitation pathways of the upper level. The probability amplitude at the second resonance point is determined by either constructive or destructive interference of both excitation pathways. This allows one to realize a fast and efficient population switching by means of varying the probe laser frequency and/or the pump laser intensity. Our simulations also show  that moderate detunings of the strong dressing laser field are actually favorable for the observation of interference effects.