Product-state control through interfering two-photon ionization routes

We have extended our studies of control of the branching ratio for photoionization of atomic barium. This control is based on an interference between two distinct photoexcitation routes, each of which is a resonantly enhanced two-photon process. We report our experimental studies of the dependence of the interference on atomic beam density, laser power, selection of intermediate states, and relative polarization of the two field components. We observe that the potential for product control increases dramatically with increasing atomic beam density and depends strongly on the laser pulse energies as well.