Extremely powerful and frequency-tunable terahertz pulses from a table-top laser-plasma wiggler

TL;DR

This paper introduces a novel plasma wiggler method using a table-top laser and near-critical density plasma to generate extremely powerful, narrow-band, and frequency-tunable terahertz pulses with high efficiency and tunability.

Contribution

It presents a new approach for generating high-power, tunable THz pulses using a plasma wiggler driven by a tabletop laser, with detailed theoretical and simulation validation.

Findings

Achieved THz pulses with >2% laser-THz energy conversion

Generated ultra-strong fields exceeding 80 GV/m

Tunable center frequency from 4.4 to 1.5 THz

Abstract

The production of broadband, terawatt terahertz (THz) pulses has been demonstrated by irradiating relativistic lasers on solid targets. However, the generation of extremely powerful, narrow-band, and frequency-tunable THz pulses remains a challenge. Here, we present a novel approach for such THz pulses, in which a plasma wiggler is elaborated by a table-top laser and a near-critical density plasma. In such a wiggler, the laser-accelerated electrons emit THz radiations with a period closely related to the plasma thickness. Theoretical model and numerical simulations predict a THz pulse with a laser-THz energy conversion over 2.0$\%$, an ultra-strong field exceeding 80 GV/m, a divergence angle approximately 20$^\circ$, and a center-frequency tunable from 4.4 to 1.5 THz, can be generated from a laser of 430 mJ. Furthermore, we demonstrate that this method can work across a wide range of laser and plasma parameters, offering potential for future applications with extremely powerful THz pulse.