Fig. 1. Schematic of light-wave‒terahertz wave hybrid waveguide. (a) Overall schematic; (b) top view; (c) front view

Fig. 2. Mode field distribution and dispersion of near-infrared light waves. (a) Distribution of 1550 nm TE mode electric field; (b) variation in near-infrared light group refractive index with wavelength

Fig. 3. Mode field distribution and dispersion of terahertz waves. (a) Metal superlattice terahertz mode field distribution; (b) metal superlattice dispersion; (c) quasi-phase matching point

Fig. 4. Nonlinear coupling coefficient. (a) Variation in the real and imaginary parts of the nonlinear coupling coefficient over one period with length; (b) Fourier transform of nonlinear coupling coefficient; (c) variation in conversion efficiency with length