Evaluation of eight nonlinear crystals for phase-matched Terahertz second-order difference-frequency generation at room temperature

Abstract

Using terahertz time-domain spectroscopy, we report the principal values of absorption coefficients and refractive indices as a function of wavelength between 0.5 and 2.0 THz of eight attractive nonlinear crystals: YCOB, BNA, LBO, CSP, AGS, CdSe, ZnO and GaP. From these data, we calculated the coherence length and phase-matching conditions associated to the emission of a THz wave from a second-order difference-frequency generation.