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.
© 2011 Optical Society of America
Original Manuscript: June 6, 2011
Revised Manuscript: July 29, 2011
Manuscript Accepted: August 21, 2011
Published: September 14, 2011
Min Li, Haifeng Pan, Yuqi Tong, Cheng Chen, Yi Shi, Jian Wu, and Heping Zeng, "All-optical ultrafast polarization switching of terahertz radiation by impulsive molecular alignment," Opt. Lett. 36, 3633-3635 (2011)