THz wave propagation in two-dimensional metallic photonic crystal with mechanically tunable photonic-bands.

Transmission and dispersion relation of THz waves in two-dimensional photonic crystal (PC) composed of metal rods are studied by using finite-difference time-domain simulation and THz time-domain spectroscopy measurement. The PC is embedded in a parallel metal plate waveguide with an air gap between the PC and one of the plates. The photonic-band-gap well-defined at small air gap narrows systematically with opening the air gap and disappears when the air gap is 2 ~ 3 times the rod height, where the two-dimensional nature of PC is destroyed.

Mechanical active control of surface plasmon properties.

We present a multilayer device which allows the control of Surface Plasmon (SP) propagation properties (propagation length and extension). A simple modification on an inner air gap thickness strongly affects SP propagation mode due to coupling with Parallel-Plate (PP) mode.