ABOVE-THRESHOLD IONIZATION BY AN ELLIPTICALLY POLARIZED FIELD - QUANTUM TUNNELING INTERFERENCES AND CLASSICAL DODGING

Measurements of above-threshold ionization electron spectra in an elli ptically polarized field as a function of the ellipticity are presente d. In the rescattering regime, electron yields quickly drop with incre asing ellipticity. The yields or lower-energy electrons rise again whe n circular polarization is approached. A classical explanation for the se effects is provided. Additional local maxima in the yields of lower -energy electrons can be interpreted as being due to interferences of electron trajectories that tunnel out at different limes within one cy cle of the field.