Coupling terahertz wave into a plasmonic waveguide by using two ribbon waveguides

Abstract We proposed the design of coupling terahertz wave into a plasmonic waveguide via using two alumina ribbon waveguides. The dispersion relation of fundamental alumina waveguide mode shows that it has intersections with plasmonic modes, resulting in the power transferred efficiently from dielectric waveguide to the structures. In experiment, a dual band metallic waveguide with two different groove depths associated with input and output alumina strips coated by polypropylene is fabricated and measured. Two plasmonic mode bands supported by plasmonic waveguide can be found because the terahertz radiation has been coupled from free space to dielectric ribbon waveguide at resonance frequencies of 0.28 THz and 0.47 THz. This coupling approach opens a novel avenue for coupling terahertz radiation and can be used for developing novel terahertz planar wave devices and circuits.