Compendium of natural hyperbolic materials

Abstract

Artificially structured hyperbolic metamaterials (HMMs) - uniaxial materials with opposite signs of permittivity for ordinary and extraordinary waves - are one of the most attractive classes of metamaterials. Their existing in nature counterpart natural (homogeneous) hyperbolic materials (NHMs) has several advantages but has not yet been analyzed extensively. Here, based on literature-available data on permittivity as a function of wavelength, we review materials with naturally occurring anisotropy of permittivity in specific wavelength ranges. We suggest the best choice of materials that may act as NHMs depending on the wavelength, strength of the dielectric anisotropy (SDA), and losses.

Long-range dipole-dipole interaction and anomalous Förster energy transfer across a hyperbolic metamaterial

“…This is to contrast with our work which addresses ENZ and ENP regions where we see the maximum enhancements. Hyperbolic materials are uni-axial materials which do exist in nature [59][60][61][62][63]. But they can also be easily fabricated by combining alternating layers of dielectric and plasmonic materials in a periodic structure, for instance.…”

Near-Field Heat Transfer between Multilayer Hyperbolic Metamaterials

“…There are many different natural bulk HM such as hexagonal boron nitride and tetradymites, which have hyperbolic bands in the visible, near-infrared or inrared regime. For an overview of different natural HM listing the different respective hyperbolic bands, we refer the reader to the references [28][29][30][31][32]. Apart from natural HM, there also exists the possibility to artificially fabricate HMMs using nanostructuration methods.…”

“…On the other hand, for applications in the infrared, it is more beneficial to combine phononpolaritonic/semiconductor and dielectric components [17,[23][24][25][26][27]. Besides such hyperbolic meta-material (HMM) structures, there exist also quite a number of natural HM [28][29][30][31][32] for applications in the visible and infrared.…”

Giant Unruh effect in hyperbolic metamaterial waveguides

“…Depending on the metamaterial design and the fabrication method used, the unit cell size in artificial optical hyperbolic metamaterials runs from s~10 nm in semiconductor-dielectric [16] and metaldielectric [13] layered structures, to s~100 nm in nanowire composites [17,18]. Very recently it was also pointed out that quite a few natural materials also exhibit hyperbolic properties in the visible range [19]. This sets s~1 nm limit on the hyperbolic material unit cell.…”