Sprecher
Beschreibung
In the past 10 years, the generation of terahertz (THz) radiation by ultrashort
laser pulses has become an active field of research due to many promising
applications in medicine, security, telecommunication and spectroscopy [1].
In gas, two-color near infrared laser pulses with moderate pump intensities
and temporally asymmetric profile trigger transverse currents
through photoionization [2]. This conversion mechanism, issued
from "photocurrents", has been proved to prevail up to sub-relativistic
intensities [3]. Here, we explore two-color plasmas beyond the relativistic threshold. Under
such conditions we numerically demonstrate that the classical THz generation
mechanism is dominated by the coherent transition radiation (CTR) of
wakefield-accelerated electrons going across the plasma/vacuum interface
[4]. Particle-in-cell (PIC) simulations performed display good
agreement with the CTR theory [5] over a wide range of laser-plasma parameters.
[1] M. Tonouchi, et al., Nature Photon. 1, 97 (2007)
[2] K. Y. Kim, et al., Nature Photon. 2, 605 (2008)
[3] P. Gonzalez de Alaiza Martinez, et al., Sci. Reports 6, 26743 (2016)
[4] W. P. Leemans, et al., Phys. Rev. Lett. 91, 074802 (2003)
[5] C. B. Schroeder, et al., Phys. Rev. E 69, 016501 (2004)
| Working group | Secondary radiation generation & applications |
|---|
