Efficient terahertz generation scheme in a thin-film lithium niobate-silicon hybrid platform

The terahertz (THz) spectral window is of unique interest for plenty of applications, yet we are still searching for a low-cost, continuous-wave, room-temperature THz source with high generation efficiency. Here, we propose and investigate a hybrid lithium niobate/silicon waveguide scheme to realize such an efficient THz source via difference-frequency generation. The multi-layer structure allows low-loss and strong waveguide confinements at both optical and THz frequencies, as well as a reasonable nonlinear interaction strength between the three associated waves. Our numerical simulation results show continuous-wave THz generation efficiencies as high as 3.5 x 10(-4) W-1 at 3 THz with high tolerance to device fabrication variations, three orders of magnitude higher than current lithium-niobate-based devices. Further integrating the proposed scheme with an optical racetrack resonator could improve the conversion efficiency to 2.1 x 10(-2) W-1. Our proposed THz source could become a compact and cost-effective solution for future spectroscopy, communications and remote sensing systems. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

A hybrid lithium niobate/silicon waveguide scheme is proposed to achieve an efficient THz source with high generation efficiency and fabrication tolerance, which could be a cost-effective solution for future spectroscopy, communications, and remote sensing systems.