Two-beam pumped terahertz parametric generator

In this study, we propose a novel, to the best of our knowledge, terahertz parametric generator capable of generating a widely tunable THz-wave using a single fixed-wavelength pump source. The pump beam is split into two beams, which are made to intersect inside a nonlinear optical crystal. The two resulting broadband parametric fluorescence components spatially overlap and mutually enhance each other at the intermediate angle between the two pump beams, and the corresponding wavelength component serves as a seed for Stokes beam generation. By varying the angle between the two pump beams, the wavelengths of the Stokes beam and the THz-wave can be controlled, and frequency tunability over the range of 1.0-2.2 THz was demonstrated.