Polarisation effects in excitation of strong perturbed atomic states

We studied experimentally the two-photon excitation of 5d7s³D₂ state of Ba atom strongly perturbed in result of ac-Stark effect realisation. The perturbation of this state was fulfilled by influence of YAG-laser radiation. For excitation of this state we used the tunable dye-laser radiation. The investigations were performed by the resonant ionization spectroscopy method. We measured the Ba⁺ ions yield caused by the ionization of Ba atoms through the two-photon resonance with perturbed 5d7s³D₂ state in cases when the electric vectors of both used radiations were parallel and orthogonal.