FDTD analysis of several terahertz devices using surface plasmon polariton waves

Two terahertz (THz) devices are analyzed using the FDTD method. One is a THz surface wave splitter using a metal disc with radially placed gratings. It is shown that the disc acts as a bi-directional frequency splitter, the frequency of which depends on grating structures. The other is a surface plasmon resonance (SPR) waveguide sensor in the THz regime, in which an InSb layer is adopted for the sensing section. The SPR response versus frequency is calculated and discussed.