THz Surface Plasmon Antennae Experiments

A diffraction grating engraved in a limited area of a flat aluminum surface serves as coupler to excite surface plasmon that propagates along the flat surface. At the flat surface edge, THz radiation is scattered into free space and impinges the edge of a similar antenna, on which a surface plasmon is excited and diffracted by a grating towards a detector. Using THz time-domain spectroscopy, we study the plasmon-plasmon coupling. We report a strong coupling efficiency over several cm of propagation in air.