PHASE-CONTROLLED QUANTUM INTERFERENCE IN 2-COLOR ATOMIC PHOTOIONIZATION

We report evidence of an interference process between two bound-free a tomic transitions induced by laser fields. Sodium atoms, initially pre pared in the 3P(1/2) excited state, are ionized by a nonresonant three -photon interaction with 1064-nm laser light and by a one-photon inter action with the third-harmonic field, at 355 nm. Interference between the two transition paths allows the control of the total ionization ra te by varying the relative phase of the laser fields. The experiment h as provided a fringe visibility as high as 42%.