The interaction of ultrashort intense laser pulses with plasma can produce electromagnetic radiation of ultra-broad spectra ranging from terahertz (THz) radiation to keV x-rays and beyond. Here we present a review of our recent theoretical and numerical investigation on high power THz generation from tenuous plasma or gas targets irradiated by ultrashort intense laser pulses. Three mechanisms of THz emission are addressed, which include the linear mode conversion from laser wakefields in inhomogeneous plasma, transient current emission at the plasma-vacuum boundaries, and the emission from residual transverse currents produced by temporally-asymmetric laser pulses passing through gas or plasma targets. Since there is no breakdown limit for plasma under the irradiation of high power lasers, in principle, all these mechanisms can lead to terahertz pulse emission at the power of beyond megawatt with the field strength of MV/cm, suitable for the study of high THz field physics and other applications.

Date Published: 7 May 2009
PDF: 13 pages
Proc. SPIE 7359, Harnessing Relativistic Plasma Waves as Novel Radiation Sources from Terahertz to X-Rays and Beyond, 735910 (7 May 2009); doi: 10.1117/12.820534

Published in SPIE Proceedings Vol. 7359:
Harnessing Relativistic Plasma Waves as Novel Radiation Sources from Terahertz to X-Rays and Beyond
Dino A. Jaroszynski; Antoine Rousse, Editor(s)