Raman excitation of rovibrational coherent and incoherent states via adiabatic passage assisted by dynamic Stark effect

We analyze rovibrational excitation by Stimulated Raman adiabatic passage using long pulses, with bandwidth much smaller than the rotational constant. Due to centrifugal distortion, a single pump and Stokes laser pulses cannot resonantly excite all the different rotational lines of any branch of the Raman spectra. Thus, the yield of the excitation decreases rapidly with increasing rotational temperature. With the aid of another pulse, inducing a dynamic Stark effect, we show that it is possible to improve the yield of the process at low temperatures. The Stark effect can be used as well to assist the adiabatic passage of coherent superposition of rotational states. Designing different pulse sequences, maximal control on the preparation of superposition states in excited vibrational levels is demonstrated.