Circularly polarized attosecond light generation from OCS molecules irradiated by the combination of linear polarized infrared and orthogonal terahertz fields

Researching ultrafast dynamics and creating coherent light sources will both benefit significantly from the establishment of polarization control in high-order harmonic generation (HHG). By employing the time-dependent density functional theory method, we investigate HHG of carbonyl sulfide molecules using a combination of a linear polarized infrared (IR) laser and a weaker orthogonal Terahertz (THz) field. Our findings show that by adjusting the amplitude of the THz field, the movement scale of electrons in the THz direction can be tuned, thereby one can control the harmonic intensity in the IR laser direction. This method allows for the creation of near-circularly polarized attosecond pulses. Furthermore, the ellipticity of the attosecond pulse may be changed by modifying the carrier-envelope phase of the IR laser pulse.

Automated summary

Research on ultrafast dynamics and coherent light sources benefits from polarization control in high-order harmonic generation (HHG). By adjusting the amplitude of a Terahertz (THz) field in combination with an infrared (IR) laser, researchers are able to control the harmonic intensity and create near-circularly polarized attosecond pulses. Additionally, changing the carrier-envelope phase of the IR laser pulse allows modification of the ellipticity of the attosecond pulse.