Coupling of near-grazing microwave photons to surface plasmon polaritons via a dielectric grating
A dielectric grating on top of a planar metal substrate is shown to couple near-grazing microwave photons to surface plasmon polaritons (SPPs). It is shown that when the grating grooves are oriented such that they are parallel to the plane of incidence (phi = 90 degrees), coupling to SPPs with both s- and p-polarized photons is possible at three different energies. It is demonstrated that one mode is coupled via p-polarized radiation and the other two modes are both coupled via s-polarized radiation. A multilayer, multishape differential grating theory allows the identities of each of the modes to be confirmed by modeling the electromagnetic fields above the metal substrate. In addition, a comparison between the experimentally derived reflectivity scans and the theoretical model is made.
Hibbins
AP
Thin Film Photonics Group, School of Physics, University of Exeter, United Kingdom.
Sambles
JR
Lawrence
CR