Emission of Terahertz Radiation from SiC
  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. 
Jared H. Strait, Paul A. George, Jahan Dawlaty, Shriram Shivaraman,   Mvs Chandrashekhar, Farhan Rana, Michael G. Spencer