Emission of Terahertz Radiation from SiC

TL;DR

This paper demonstrates strong broadband terahertz radiation emission from 6H-Silicon-Carbide (SiC) excited by optical pulses, with detailed characterization of its nonlinear optical properties and high spectral signal-to-noise ratio.

Contribution

It provides the first measurement of the nonlinear susceptibility tensor ratio and complex index of refraction of SiC at THz frequencies, elucidating the generation mechanism of terahertz radiation.

Findings

High signal-to-noise ratio (>1000) in terahertz emission

Terahertz radiation generated via optical rectification in SiC

Measured nonlinear susceptibility tensor ratio and refractive index at THz frequencies

Abstract

We report the emission of strong coherent broadband terahertz radiation from 6H-Silicon-Carbide (SiC) excited with optical pulses. The measured terahertz spectral signal-to-noise ratio is better than one thousand. We determine that the terahertz radiation is generated via second order optical nonlinearity (optical rectification). We present a measurement of the ratio of nonlinear susceptibility tensor elements $\chi_{zzz}^{(2)}/\chi_{zxx}^{(2)}$ and the complex index of refraction of silicon carbide at THz frequencies.