THz generation from relativistic plasmas driven by near- to far-infrared laser pulses

Abstract

Terahertz pulse generation by ultra-intense two-color laser fields ionizing gases with near- to far-infrared carrier wavelength is studied from particle-in-cell (PIC) simulations. For long wavelength ($10.6\mu$m) promoting a large ratio of electron density over critical, photoionization is shown to catastrophically enhance the plasma wakefield, causing a net downshift in the optical spectrum and exciting THz fields with tens of GV/m amplitude in the laser direction. This emission is accompanied by coherent transition radiation (CTR) of comparable amplitude due to wakefield-driven electron acceleration. We analytically evaluate the fraction of CTR energy up to 30 % of the total radiated emission including the particle self-field and numerically calibrate the efficiency of the matched blowout regime for electron densities varied over three orders of magnitude.

arXiv comment5 pages, 5 figures

References in corpus (6)

• Generating multi-GeV electron bunches using single stage laser wakefield acceleration in a 3D nonlinear regime
• Terahertz-driven linear electron acceleration
• THz pulses over 50 millijoules generated from relativistic picosecond laser-plasma interactions
• Laser wakefield acceleration with mid-IR laser pulses
• Sequential terahertz pulse generation by photoionization and coherent transition radiation in underdense relativistic plasmas
• Boosting terahertz-radiation power with two-color circularly polarized midinfrared laser pulses

Cited by in corpus (1)

• Generation of synchronized high-intensity x-rays and mid-infrared pulses by Doppler-shifting of relativistically intense radiation from near-critical-density plasmas