Controlling the generation of elliptically polarized isolated attosecond pulses from mixed gases with a polarization-gating technique

The generation of elliptically polarized attosecond pulses has become a crucial issue due to the growing interest in its application to probing circular dichroism and chirality in matter. Here, we propose a method capable of generating isolated attosecond pulses (IAPs) with near-circular polarization. Through the combination of the mixed gases scheme with a polarization gating laser field, we obtain an IAP with an ellipticity of 0.91 and a pulse duration of 290 as. Our analysis indicates that the polarization of attosecond pulses is predominantly influenced by the mixed gases, specifically by the selective interference between the recombination dipole moments of different gas components. In contrast to polarization, the temporal profile of attosecond pulses mainly depends on the laser field. Our approach achieves independent control of the polarization and temporal properties of IAPs by adjusting the gas mixture and the polarization gating laser field, respectively, thus paving an effective and convenient way to generate and control elliptically polarized IAPs.