Abstract
Radially polarized intense terahertz (THz) radiation behind a thin foil irradiated by ultrahigh-contrast ultrashort relativistic laser pulse is recorded by a single-shot THz time-domain spectroscopy system. As the thickness of the target is reduced from 30 to 2 µm, the duration of the THz emission increases from 5 to over 20 ps and the radiation energy increases dramatically, reaching per pulse, corresponding to a laser-to-THz radiation energy conversion efficiency of . The efficient THz emission can be attributed to reflection (deceleration and acceleration) of the laser-driven hot electrons by the target-rear sheath electric field. The experimental results are consistent with that of a simple model as well as particle-in-cell simulation.
- Received 3 February 2016
- Revised 27 April 2016
DOI:https://doi.org/10.1103/PhysRevE.94.033206
©2016 American Physical Society