Difference frequency generation of narrow-band THz radiation on the basis of a parametric three-wave interaction in a ZnTe crystal

We consider theoretically difference frequency generation of terahertz (THz) radiation in a collinear one-chip scheme with distributed feedback realized by the parametric interaction of optical waves in a periodically inhomogeneous zinc telluride (ZnTe) crystal with a quadratic nonlinearity. In the approximation of inexhaustible optical pumping at a wavelength λ=0.77μm, the possibility of obtaining a parametric generation with high-efficiency optical-THz conversion (more than 10−2 at temperature 80 K) is shown with an extremely narrow generation line of less than 0.01 THz. The conversion efficiencies at temperatures 80, 200 and 295 K are studied. The obtained results can be used to construct narrow-band THz lasers with a power of about 105 W/cm2 in the quasi-continuous generation regime.