Abstract-Using submicron dielectric coatings to reduce terahertz surface plasmon losses on metals

V V Gerasimov, A K Nikitin, B A Knyazev, A G Lemzyakov,  I A Azarov

http://iopscience.iop.org/article/10.1088/1742-6596/1092/1/012041/pdf

Terahertz (THz) surface plasmons (SPs) are very promising for developing transmission lines and new photonic devices. Energy losses during propagation of SPs plays important role for these applications. We experimentally studied attenuation of SPs along plane and convex (curvature radius of 60 mm) gold surfaces coated with submicron dielectric (ZnS) layers using monochromatic radiation (λ=130 μm) of the Novosibirsk free-electron laser. The optimal dielectric thicknesses d*, corresponding to the minimum energy losses of SPs, were found. The SP attenuation coefficients α were about 100 times higher for convex surfaces than for plane surfaces, which means intensive radiative losses on the surface bend. A ZnS coating with d1*≈0.025 μm on a plane gold surface reduced α by 20 % as compared with bare gold; coating with d2*≈1 μm on convex surface, three times.