Ellipticity control of terahertz high-harmonic generation in a Dirac semimetal

TL;DR

This paper demonstrates efficient control of terahertz high-harmonic generation in a Dirac semimetal, showing tunable harmonic yield and polarization via ellipticity, with potential applications in optical signal processing.

Contribution

It provides experimental and theoretical insights into controlling high-harmonic generation in Dirac semimetals through ellipticity, a novel approach in nonlinear terahertz optics.

Findings

Third-harmonic yield and polarization are tunable by ellipticity.

Terahertz-field driven intraband kinetics explain the tunability.

Potential for nonlinear optical applications in Dirac materials.

Abstract

We report on terahertz high-harmonic generation in a Dirac semimetal as a function of the driving-pulse ellipticity and on a theoretical study of the field-driven intraband kinetics of massless Dirac fermions.Very efficient control of third-harmonic yield and polarization state is achieved in electron-doped Cd$_3$As$_2$ thin films at room temperature. The observed tunability is understood as resulting from terahertz-field driven intraband kinetics of the Dirac fermions. Our study paves the way for exploiting nonlinear optical properties of Dirac matter for applications in signal processing and optical communications.