Surface-Emitted Terahertz-Wave Difference-Frequency Generation in Periodically Poled Lithium Niobate Ridge-Type Waveguide

Abstract

We demonstrated surface-emitted terahertz (THz)-wave difference-frequency generation from a periodically poled magnesium-oxide-doped lithium niobate (PPMgLN) ridge-type optical waveguide. The periodic structure in the direction of propagation of the incident laser light was sufficient for surface emission because the incident laser light was confined within a waveguide. Tunable THz waves were generated at around 1 and 1.5 THz using two ridge-type PPMgLN waveguides. The generated THz wavelengths were determined under the quasi-phase matching condition.