Terahertz switch based on waveguide structures

We propose a terahertz switch based on nonlinear materials, which consists of a straight-through waveguide and two micro-ring waveguides with a concentric circle structure. When pump laser is applied, a nonlinear effect is generated at the concentric circle structure, which enables the coupling of the straight waveguide and the concentric micro-ring waveguide to switch between a resonant state and a non-resonant state, thereby realizing switching OFF and ON of terahertz waves. The terahertz switch exhibits a modulation depth of 99.45%, an extinction ratio of 22.56 dB, and a switching speed of 6.7 ps at a frequency of 3.31 THz under an external laser pump. The device has a small size and can be integrated with CMOS technology, which is expected to be applied in future terahertz communication and sensing systems.