Millimeter Wave Phase Shifter Based on Optically Controlled Carbon Nanotube Layers

Surfaces with tunable impedance are usually lossy at high frequencies, which limits the design of millimeter wave and Terahertz devices. This work experimentally demonstrates a phase shifter based on single-walled carbon nanotubes and dielectric rod waveguides in the 220-330 GHz frequency range. Thin carbon nanotube layers are used as a tunable impedance surface with the dielectric properties optically controlled by laser illumination.