High field terahertz emission from relativistic laser-driven plasma wakefields

TL;DR

This paper presents a novel method for generating high-intensity terahertz radiation in the 1-10 THz range by using relativistic laser interactions with plasma, involving pulse evolution and electron current excitation.

Contribution

It introduces a new approach leveraging local pump depletion and pulse shaping to produce strong THz emission via plasma currents, demonstrated through particle-in-cell simulations.

Findings

Achieved GV/cm level THz fields in simulations

Identified pulse evolution mechanism for THz generation

Demonstrated effectiveness in 1D and 2D models

Abstract

We propose a method to generate high field terahertz (THz) radiation with peak strength of GV/cm level in the THz frequency gap range 1-10 THz using a relativistic laser interaction with a gaseous plasma target. Due to the effect of local pump depletion, an initially Gaussian laser pulse undergoes leading edge erosion and eventually evolves to a state with leading edge being step function. Interacting with such a pulse, electrons gain transverse residual momentum and excite net transverse currents modulated by the relativistic plasma frequency. These currents give rise to the low frequency THz emission. We demonstrate this process with one and two dimensional particle-in-cell simulations.