Backward terahertz difference frequency generation via modal phase-matching in a planar LiNbO3 waveguide

The backward difference frequency generation process is used to produce narrowband terahertz radiation via modal phase-matching in a SiO2-LiNbO3-air planar waveguide. The TM0 pump mode, TE0 signal mode, and TE0 or TE2 idler modes are selected to satisfy the backward difference frequency generation phase-matching condition, thus allowing narrowband (i.e., <100GHz linewidth) terahertz radiation generation in the spectral range of 2.4-3.2 THz. To date, this is the first investigation of terahertz radiation generation in a waveguide via the modal phase-matched backward difference frequency generation process.