INVESTIGATION OF A 2-AUTOIONIZING-LEVEL SYSTEM COUPLED BY A STRONG LASER FIELD

The coherent resonant coupling of two autoionizing states of magnesium by an intense electromagnetic field is investigated experimentally by means of ionization and energy-selected photoelectron spectra probed from the ground state of the atom. The resulting effect of a drastic r eduction in the ionization of the system is interpreted as the splitti ng of the two states achieved through their mixing by the field. A com plete theoretical treatment of the problem employing the density matri x formalism is presented, reproducing the effects observed and explain ing the phenomenon in terms of the relative populations of the states in the system.