Controlling ionization products through laser-induced continuum structure

We report on the observation of the modification of the two spin-orbit ionization continua of Xe through laser-induced continuum structure (LICS). The radiative decay of the Xe ground state into the two electronic continua that correspond to the two fine-structure levels of the ground state of the Xe+ ion can be varied by electromagnetically embedding a bound state of the atom into the two continua. The dressed P-2(1/2) continuum, probed from the atomic ground state through three-photon absorption, exhibits a clear induced structure, while the (2)p(3/2) continuum possesses no observable structure under the present experimental conditions, as manifested through high-resolution photoelectron spectra. The modified ionization ratio is controlled by the wavelength of the dressing field.