title: All-optical ultrafast polarization switching of terahertz radiation by impulsive molecular alignment.
abstract: We experimentally demonstrate ultrafast polarization switching of terahertz (THz) radiation generated by dual-color driving pulses composed of orthogonally polarized fundamental and second-harmonic waves, which can be controlled by field-free molecular alignment in air by modulating the relative phase between the two field components as a transient dynamic wave plate. By fine-tuning the time delay to properly match the molecular alignment revivals, a significant polarization modulation of the THz radiation is observed and both linearly and elliptically polarized THz radiations can be obtained.
authors.affiliation: State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, China.
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: Haifeng
authors.initials: H
authors.lastname: Pan
authors.forename: Yuqi
authors.initials: Y
authors.lastname: Tong
authors.forename: Cheng
authors.initials: C
authors.lastname: Chen
authors.forename: Yi
authors.initials: Y
authors.lastname: Shi
authors.forename: Jian
authors.initials: J
authors.lastname: Wu
authors.forename: Heping
authors.initials: H
authors.lastname: Zeng