Terahertz wave generation using type II phase matching polarization combination via difference frequency generation with LiNbO3

We present terahertz (THz) wave generation using type II phase matching polarization combination via difference frequency generation (DFG) with lithium niobate (LiNbO3) crystal. A collinear phase matching has not been realized so far because LiNbO3 crystal has a large absorption and high refractive index dispersion. In this paper we proposed that using type II phase matching is able to avoid these defects and generate the THz wave. We experimentally demonstrated the forward and backward collinear type II phase matching method, and confirmed that THz wave is generated by using simple equipment. This method will be applied for the applications for a small THz wave sources. (C) 2015 The Japan Society of Applied Physics