On the role of coupling in mode selective excitation using ultrafast pulse shaping in stimulated Raman spectroscopy

A semiclassical model of the coherent control of excitation of Raman transitions in two coupled two-level systems was investigated using a broadband shaped laser pulse. The selective excitation of one of the two, two-level systems was also studied as a function of coupling strength and initial phases. A relative phase equal to π was found to project the system into a dark state. The results show that depending on the intensity of the field, the initial phase causes predominance of the coherence of one two-level system with respect to another.