Absorption of near-fields through hyperbolic metamaterials with finite thickness

We use spectral theory to analyze the radiation of elementary dipoles located close to homogeneous hyperbolic metamaterials (HMs) with finite thickness, focusing on the effect of losses in the HM. We show that for loss tangents (due to anisotropy) smaller than or equal to 10^-1 the effect of the HM on dipole radiation is twofold: first, it induces an enhancement in the emitted power; second, most of this power is directed toward the HM itself. Then, we investigate the power scattered by a plasmonic nanosphere under plane wave incidence on top of a realistic multilayered HM with finite thickness. The multilayered HM, when homogenized, exhibits loss tangents of the same order of our previous analysis. We finally report that the multilayered HM enhances the nanosphere´s scattered power, which is mainly directed toward the multilayered HM, in agreement with results relative to impressed dipoles.