Absorption-type terahertz wave switch based on Kerr media

We design an ultra-fast absorption type switch operating in the terahertz wave regime. The device consists of dual metallic layers for allowing near-perfect absorption due to electric and magnetic resonances, and a nonlinear Kerr-media layer for actively manipulating device absorption. In this novel design, the center frequency of the absorption peak can be dynamically shifted by adjusting the incident external pump laser intensity. By using the finite-difference time-domain method, the switch properties of terahertz wave absorption in sub-wavelength period structures on the Kerr-media layer under different incident optical intensities have been investigated. The simulation results demonstrate that device absorption can be flexibly tuned from near unity to zero by adjusting the incident optical intensity. It is extremely versatile to control the ultra-fast terahertz switch by varying the incident optical intensity. These results provide a useful guide for the developments of terahertz wave functional components.