State selectivity and eigenstate control in molecules using multiple CW lasers

A novel method for designing target states with desirable properties by using a strong laser field has been developed. In a molecular system with two closely spaced levels application of a strong laser is shown to lead to a controllable mixture of states. A "control equation" governing the relation between the Rabi frequency and the detuning of the coupling field has been derived on the basis of the dressed-states approach.; A more intuitive way of achieving mixing in the perturbed eigenstates has been investigated by using the Autler-Townes (AT) effect in the case of weak initial mixing. A condition for resonant enhancing of the mixing has been obtained.; The theoretical analysis is based on the dressed states approach as well as the density matrix formalism. While the dressed states approach explains the creation of the target states under the action of the strong coupling field, the density matrix formalism accounts also for such physical phenomena as spontaneous decay of the molecular levels and describes the molecular absorption and level populations. Thus, it can be used to demonstrate the creation of the target states via the absorption behavior of the system in the presence of the strong field.; The target state creation and the Autler-Townes splitting have been applied to realistic systems (molecular lithium) for the case of singlet-triplet initial mixing. The control equations as well as the condition for the AT effect have been modified to reflect the magnetic quantum number (MJ) degeneracy in all the molecular levels. The design of target states and states mixed via AT splitting with a pre-selected magnetic quantum number has been demonstrated by calculating the absorption spectra of the weak field. The possibility for direct measurement of spin-orbit interaction has been shown even in the presence of level degeneracy. The prospect of target states creation and molecular magnetic sublevel selectivity has been discussed in case of inhomogeneously broadened media.