Scheme for multistep resonance photoionization of atoms - art. no. 013401

Traditional schemes for multistep resonance photoionization of atoms let ev ery employed laser beam interact with the atoms simultaneously. In such a s ituation, analyses via time-dependent Schrodinger equation show that high i onization probability requires all the laser beams must be intense enough. In order to decrease laser intensity, we proposed a scheme that the laser b eam used to pump the excited atoms (in a higher bound state) into an autoio nization state does not interact with the atoms until all the population is transferred by the other lasers from a ground state to the bound state. As an interesting example, we examined three-step photoionization of U-235 Wi th our scheme, showing that the intensity of two laser beams can be lowered by two orders of magnitude Without losing high ionization probability.