PRODUCT-STATE CONTROL THROUGH INTERFERING 2-PHOTON IONIZATION ROUTES

We have extended our studies of control of the branching ratio for pho toionization of atomic barium. This control is based on an interferenc e between two distinct photoexcitation routes, each of which is a reso nantly enhanced two-photon process. We report our experimental studies of the dependence of the interference on atomic beam density, laser p ower, selection of intermediate states, and relative polarization of t he two field components. We observe that the potential for product con trol increases dramatically with increasing atomic beam density and de pends strongly on the laser pulse energies as well.