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.
This paper was presented at the SPIE conference indicated above but inadvertently published by SPIE subsequent to its publication in another journal (Optics Letters). The paper has therefore been withdrawn from the SPIE Proceedings by the author and the publisher. The journal paper can be accessed at http://dx.doi.org/10.1364/OL.34.002730.