Photo-excited terahertz switch based on composite metamaterial structure

A photo-excited terahertz switch based on a composite metamaterial structure was designed by integration of photoconductive silicon into the gaps of split-ring resonators. The conductivity of the silicon that was used to fill the gaps in the split-ring resonators was tuned dynamically as a function of the incident pump power using laser excitation, leading to a change in the composite metamaterial structure's properties. We studied the transmission characteristics of the composite metamaterial structure for various silicon conductivities, and the results indicated that this type of composite metamaterial structure could be used as a resonance frequency tunable terahertz metamaterial switch. We also designed other structures by filling different gaps with silicon, and proved that these structures could be used as terahertz metamaterial switches can change the working mode from a single frequency to multiple frequencies.

Graphical abstractAs shown in figure above, a resonant dip was obtained at 2.128 THz when the silicon conductivity was 0 S/m. With increasing silicon conductivity, the transmission intensity at the dip increases and the resonant frequency gradually shifts. The resonant dip at 2.128 THz disappeared when the silicon conductivity increased to 300,000 S/m. At the same time, a new resonant dip appeared at 1.091 THz, and is shown as a black line in figure above.Figure optionsDownload full-size imageDownload high-quality image (279 K)Download as PowerPoint slide