Slowing down the speed of terahertz guiding modes of a metal air-gap waveguide by using a coupled plasmonic cavity

We present numerical and experimental demonstration of slowing down the speed of terahertz guiding modes of a metal air-gap waveguide by using a one-dimensional coupled plasmonic cavity. The speed of terahertz guiding modes gets slower as a distance between metal plates of the waveguide decreases because the coupling strength between cavities gets weaker as the distance decreases. The coupled plasmonic cavities in a metal air-gap waveguide could be useful in enhancing the interaction between the guiding modes and matters and manipulating terahertz waves in a time domain. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4768916]