Hyperbolic metamaterial as super absorber for scattered fields generated at its surface

Abstract

We show that hyperbolic metamaterials (HMs) that exhibit hyperbolic wave-vector dispersion diagrams possess two important features related to super absorption: The total power scattered by a nanosphere is (i) greatly enhanced when placed at the HM surface, compared to other material surfaces, and (ii) almost totally directed into the HM. We show that these two features are peculiar of HM interfaces, and we support them using a spectral theory study of transverse-electric and magnetic waves scattered by a subwavelength nanosphere. We analyze the nanosphere's scattered power absorbed by various substrate configurations. We also consider various nanosphere materials.

Absorption of near fields generated by a two-dimensional array of dipoles above a hyperbolic metamaterial

“…When the period is increased both tot free space / P P and down up / P P are enhanced. This is in good agreement with the results in [1] drawn for a single dipole. Moreover a sharp peak appears for 300 nm a b = = case, which is attributed to the coupling to a surface mode.…”

“…For example, when h is increased from 5 to 25 nm as reported in Fig. 3, the two ratios above degrade significantly, confirming the importance of evanescent coupling of the field from the dipoles to the HM, in agreement with the results drawn in [1] for a single dipole. VI.…”

“…The wave admittances toward -z direction can be straightforwardly evaluated using transfer matrix method and the Bloch impedance of the unit cell of HM [1]. Wave propagation in HM impacts dramatically the power splitting toward up and down.…”

“…HMs allow for redistribution of power in a (relatively) wide spatial spectrum compared to common dielectrics, leading to novel phenomena such as enhancing the power scattered by nanoparticles [1] or emitted power by imposed dipoles [1]- [3] located on HM surfaces. Interestingly, this power is mostly directed to HM where it can be absorbed.…”

Dual-gated tunable absorption in graphene-based hyperbolic metamaterial

“…HMMs can be designed for use in efficient and innovative absorbers to enhance the decay rate of emitters near the surface. 12 Tumkur 13 showed that metallic and lamellar metal-dielectric HMM substrates can tune and enhance the absorption of thin dye-doped polymeric films.…”