Precise control of state-selective excitation in stimulated Raman scattering

Multiphoton transitions can be manipulated by tailoring the ultrashort laser pulse. In this paper, we propose two schemes for achieving precise control of the selective excitation between two excited states in stimulated Raman-scattering process. We theoretically demonstrate that by properly designing the spectral phase distribution, the stimulated Raman transition probability for one excited state is kept at zero or a maximal value, while that for the other excited state can be continuously tuned over a wide range. Furthermore, the influence of the spectral bandwidth on the tunable range by the two schemes is discussed. We conclude that these schemes have significant application to the selective excitation of femtosecond coherent anti-Stokes Raman scattering.