PHASE-DEPENDENT SIDELOBES IN HIGH-ORDER ABOVE-THRESHOLD IONIZATION INA BICHROMATIC LASER FIELD

We investigate the recently observed sidelobes in the angular distribu tion of high-order above-threshold ionization (ATI) by placing an atom in a bichromatic laser field of frequencies omega and 2 omega where b oth components have a relative phase phi. Using an improved Keldysh-Fa isal-Reiss (KFR) model, in which the Coulomb effects of the parent ion s are taken into account, we show that even for a second field of very low intensity, drastic changes in the angular distributions occur as a function of the phase phi. Relations of our work to previous investi gations are established.