ELECTRON-ATOM IONIZING COLLISIONS IN THE PRESENCE OF A BICHROMATIC LASER FIELD

A theory of electron-atom ionizing collisions in the presence of a bic hromatic laser field is developed. The incident and scattered electron of high energy is described by Volkov states, the atomic ground state is dressed by the laser field to first order in the electric-field st rength, and the atomic continuum state that corresponds to the ejected slow electron is dressed by the laser field to all orders in the fiel d strength, but in an approximate way. It is shown that the dressing o f these continuum states is mainly responsible for the different effec ts that a bichromatic laser field introduces into this process. These effects are more pronounced compared to similar effects recently obser ved in an analysis of the target dressing in free-free transitions in a bichromatic laser field. The possibility of the coherent phase contr ol is analyzed and it is shown that the triple differential cross sect ion (TDCS) can be changed by almost one order of magnitude by changing the relative phase between the two laser field components. The TDCS a s a function of the relative phase, the number of absorbed (emitted) p hotons, and the laser electric-field strength shows a specific behavio r that is mainly determined by the properties of the generalized Besse l functions appearing In our results. It is also shown that these effe cts are particularly pronounced for rather small scattering angles of the fast electron.