Surface-emitted continuous-wave terahertz radiation using periodically poled lithium niobate

Continuous-wave (CW) terahertz radiation based on nonlinear difference frequency mixing (DFM) of two laser lights outputs is demonstrated. The surface-emitting method generated THz frequency radiation in the perpendicular direction of incident laser light by quasi-phase-matching. Periodically poled lithium niobate (PPLN) served as the nonlinear material for this surface-emitting method. In this case, two diode laser wavelengths of 1.5 mu m can be applied as DFM sources, within the range of telecommunications technology.