Potential scattering in a strong multicolour laser field
Potential scattering in a strong elliptically polarized multicolour laser field is considered. The first result is the off-shell low-frequency approximation for scattering with emission (absorption) of L photons. A simple result for the total cross section is obtained using the optical theorem. In the case of a linearly polarized multicolour laser field a generalization of the on-shell Kroll-Watson-type low-frequency approximation is derived. Numerical results, obtained using the [1, 1] Pade approximant to the off-shell low-frequency T matrix for scattering on the Yukawa potential in a bichromatic laser field, are compared with the Varro and Ehlotzky results. The symmetry and asymmetry properties of the scattered electron spectra, as well as the symmetry breaking at higher laser field intensity, are analysed. It was observed that the differential cross section for scattering in a bichromatic laser field as a function of L. can have pronounced maxima. The positions of these maxima are determined by the generalized Bessel function properties and can be controlled by changing the laser field intensity and the relative phase between the laser field components.