Intense THz radiation from laser plasma with controllable waveform and polarization

Abstract

We demonstrate the generation of waveform-controlled THz radiation from air plasma that is produced when carrier envelope phase (CEP) stabilized few-cycle laser pulses undergoes filamentation in ambient air. Elliptically polarized THz waves are generated from air plasma induced by circularly polarized few-cycle laser pulses. Our results reveal that electric field asymmetry in rotating directions of the circularly polarized few-cycle laser pulses produces the enhanced broadband transient currents, and the phase difference of perpendicular laser field components is partially inherited in the generation process of THz emission.