Generating attosecond pulses with controllable polarization from cyclic H₃²⁺ molecules by bichromatic circular fields

【摘要】 We investigate the polarization properties of harmonics from the cyclic H₃²⁺ molecular ions in tailored bichromatic counter-rotating circularly polarized（BCCP） fields by solving the time-dependent Schr?dinger equation. The allowed harmonics and their helicities are associated with the symmetry compatibility of the field-target systems, and large intensity difference between adjacent harmonics with opposite helicities appears in a wide spectral range when the BCCP field is at certain rotation angles. We try to explain the intensity difference by using a recombination model based on the quantum-orbit theory and by analyzing the ionization pathways. Moreover, to synthesize attosecond pulse trains with tunable polarization, the intensity difference is manipulated by introducing a seed XUV field, and by changing the relative amplitude ratio as well as the helicity of BCCP fields.更多还原

【Abstract】 We investigate the polarization properties of harmonics from the cyclic H₃²⁺ molecular ions in tailored bichromatic counter-rotating circularly polarized（BCCP） fields by solving the time-dependent Schr?dinger equation. The allowed harmonics and their helicities are associated with the symmetry compatibility of the field-target systems, and large intensity difference between adjacent harmonics with opposite helicities appears in a wide spectral range when the BCCP field is at certain rotation angles. We try to explain the intensity difference by using a recombination model based on the quantum-orbit theory and by analyzing the ionization pathways. Moreover, to synthesize attosecond pulse trains with tunable polarization, the intensity difference is manipulated by introducing a seed XUV field, and by changing the relative amplitude ratio as well as the helicity of BCCP fields.更多还原