SELECTIVE EXCITATION VIA THE CONTINUUM AND SUPPRESSION OF IONIZATION

Two laser pulses that overlap in time have been successfully used for coherent excitation of a molecule or atom to a desired state. An intermediate state that is at or near resonance with the laser frequencies has been used in past experiments and calculations. Here we replace this intermediate state by a continuum of intermediate states. An analytic solution of a simple model suggests that the continuum can be used in such an excitation scheme, provided that the laser pulses are arranged in the so-called counter-intuitive order. We use a special case of this solution to relate this work to ionization suppression and coherent population trapping.