Generation of terahertz radiation from ionizing two-color laser pulses in Ar filled metallic hollow waveguides

TL;DR

This study numerically investigates how ionizing two-color femtosecond pulses in Ar-filled metallic hollow waveguides generate broad-spectrum THz radiation, resulting in near-infrared single-cycle pulses with high efficiency.

Contribution

It demonstrates the spectral broadening and generation of near-infrared single-cycle pulses through numerical simulations of THz generation in metallic hollow waveguides.

Findings

Spectrum extends from hundreds of GHz to ~150 THz

Nearly single-cycle near-infrared pulses are produced

Spectral filtering achieves up to 0.25% efficiency

Abstract

The generation of THz radiation from ionizing two-color femtosecond pulses propagating in metallic hollow waveguides filled with Ar is numerically studied. We observe a strong reshaping of the low-frequency part of the spectrum. Namely, after several millimeters of propagation the spectrum is extended from hundreds of GHz up to ~150 THz. For longer propagation distances, nearly single-cycle near-infrared pulses with wavelengths around 4.5 um are obtained by appropriate spectral filtering, with an efficiency of up to 0.25%.