Proposal and numerical verification of an ultrasmall terahertz source using integrated photonic crystal waveguides for highly efficient differential frequency generation

Abstract We propose and numerically investigate integrated photonic crystal waveguides (PhC-WGs) formed in a semiconductor slab to realize an ultrasmall highly efficient terahertz (THz) wave source. The structure consists of straight PhC-WG with low-group-velocity low-dispersion (LVLD) for difference frequency generation (DFG) connected two PhC-WGs introduce fundamental lights into the LVLD PhC-WG. light propagating through each designed enhance their electric fields by slow-light effect is efficiently coupled owing reduced refractive index differences at boundaries heterostructures. DFG from was simulated, temporal intensity oscillation corresponding clearly observed. By comparing intensities structures strip WG, estimated more than 100 times higher that WG. These results indicate effectiveness proposed heterostructure application THz source footprint compared conventional materials.