A practical scheme for generating isolated elliptically polarized attosecond pulses using bi-chromatic counter rotating circularly polarized laser fields

摘要

Spectra of circularly polarized harmonics is calculated by numericallysolving the Time-Dependent Schr\"{o}dinger Equation for a 2D model of Ne atomusing circularly polarized fundamental with counter-rotating second harmoniclaser fields. We demonstrate strong asymmetry between left- and right-circularly polarized harmonics when a ground state with p-type symmetry isused. It arises due to the circular polarization of individual attosecondpulses in the generated pulse train. Reducing the length of thecounter-rotating drivers and introducing a small time-shift between them allowsto generate a single elliptically polarized attosecond pulse.