Planar plasmonic terahertz guided-wave devices

We describe the experimental realization of planar plasmonic THz guided-wave devices using periodically perforated metal films. These perforated films behave as effective media for which the dielectric function can be broadly engineered. We initially use transmission measurements to measure the complex dielectric constants of these effective media and show experimentally that the effective plasma frequency corresponds to the cutoff frequency of the rectangular apertures. Using these structures, we demonstrate not only straight planar THz waveguides, but also more complex devices such as Y-splitters and 3-dB couplers. In each of these embodiments, we demonstrate that the propagating THz radiation is well confined in both the in-plane and out-of-plane axes. This approach opens exciting new avenues for both passive and active THz guided-wave devices and circuits.