2020/05/11 by J. Déchard, X. Davoine, Déchard, J. +5
Engineering · Physics and Astronomy · #FOS: Physical sciences #Laser-Plasma Interactions and Diagnostics #Laser-induced spectroscopy and plasma #Plasma Physics (physics.plasm-ph) #Terahertz technology and applications
paper · pdf · doi:10.48550/arxiv.2005.05425
openalex publication_date 2020/05/11 · openalex created_date 2020/05/21 · openalex updated_date 2026/07/28
Using high-resolution, two-dimensional particle-in-cell simulations, we investigate numerically the mechanisms of terahertz (THz) emissions in submicron-thick carbon solid foils driven by ultraintense (∼ 1020 \rm W cm-2), ultrashort (30 \rm fs) laser pulses at normal incidence. The considered range of target thicknesses extends down to the relativistic transparency regime that is known to optimize ion acceleration by femtosecond laser pulses. By disentangling the fields emitted by longitudinal and transverse currents, our analysis reveals that, within the first picosecond after the interaction, THz emission occurs in bursts as a result of coherent transition radiation by the recirculating hot electrons and antenna-type emission by the shielding electron currents traveling along the fast-expanding target surfaces.