Gao, Yuan; Zhang, Yizhu; Zhang, Kaixuan; Gan, Ziyang; Yan, Tian -Min; Jiang, Yuhai

OPTICS LETTERS

2023, 48, 1539-4794

Gao, Yuan; Zhang, Yizhu; Zhang, Kaixuan; Gan, Ziyang; Yan, Tian -Min; Jiang, Yuhai

The orientation and ellipticity of terahertz (THz) polariza-tion generated by a two-color strong field not only casts light on underlying mechanisms of laser-matter interaction, but also plays an important role for various applications. We develop the Coulomb-corrected classical trajectory Monte Carlo (CTMC) method to well reproduce the joint measure-ments, that the THz polarization generated by the linearly polarized 800 nm and circularly polarized 400 nm fields is independent on two-color phase delay. The trajectory analysis shows that the Coulomb potential twists the THz polarization by deflecting the orientation of asymptotic momentum of electron trajectories. Further, the CTMC cal-culations predict that, the two-color mid-infrared field can effectively accelerate the electron rapidly away from the par-ent core to relieve the disturbance of Coulomb potential, and simultaneously create large transverse acceleration of trajec-tories, leading to the circularly polarized THz radiation. (c) 2023 Optica Publishing Group