Lithium niobate and lithium tantalate based scalable terahertz pulse sources in reflection geometry

A new type of THz source, working in reflection geometry, is proposed, where the pulse-front-tilt is introduced by a periodically micro-structured metal profile. For optical coupling, high refractive index nanocomposite fluid is used between the nonlinear optical material and the structured metal surface. Numerical simulations predict similar to 87 and similar to 85% optimized diffraction efficiencies for lithium niobate and lithium tantalate at 1030 and 800 nm pump wavelengths. The largest diffraction efficiencies can be achieved for a larger refractive index of the nanocomposite fluid than the index of the nonlinear material, for both cases. THz generation efficiencies of similar to 3 and similar to 1% are predicted for lithium niobate and lithium tantalate, respectively. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement