Surface and volume phonon polaritons in a uniaxial hyperbolic material: optic axis parallel versus perpendicular to the surface

Abstract

Uniaxial hyperbolic materials enable excitation of phonon polaritons with utrahigh wavevectors that have been shown to be promising for many optical and thermal radiative applications and thus have attracted much attention recently. However, the characteristics of surface and volume phonon polaritons excited with uniaxial hyperbolic materials that exhibit in-plane anisotropy or in-plane isotropy have not been discussed thoroughly and some issues have so far remained elusive. In this paper, we conducted a comprehensive investigation on surface and volume phonon polaritons in a bulk or a thin slab of hexagonal boron nitride (hBN). We clarified the excitation, characteristics and topology of surface and volume phonon polaritons in such a uniaxial hyperbolic material. In particular, we showed that hyperbolic surface phonon polaritons (HSPhPs) can exist in the Type I hyperbolic band of hBN with confined wavevectors when the optic axis (OA) is parallel to the surface. For a thin hBN slab, we revealed a split of HSPhPs and a smooth transition between HSPhPs and HVPhPs in the Type II hyperbolic band. Furthermore, we also identified non-Dyakonov surface phonon polaritons excited without evanescent ordinary waves. These findings may extend the understanding of phonon polaritons in hyperbolic materials and offer new theoretical guidance for the design of infrared optical devices with hyperbolic materials.

Optical axis-driven modulation of near-field radiative heat transfer between two calcite parallel structures

“…Asymptotes of v-HP modes are demonstrated by two white dashed lines. 30,43 Fig. 7 shows the ETC at an angular frequency of 2.86 Â 10 14 rad s À1 (band 3, type II hyperbolic band) for different OA.…”

“…28 The matrix D is obtained by . According to the theoretical investigation of HPs in a hyperbolic material (hBN), the dispersion relation of v-HPs and s-HPs in a thin sheet of hyperbolic material can be derived as 42,43 where , where k x and k y are the wavevector in the x - and y -axis, respectively. When the OA of CaCO 3 is along the x -axis, the regions in the k x – ky plane where v-HPs can occur are bounded respectively by the curves defined as 30 …”

“…À Á À1 . According to the theoretical investigation of HPs in a hyperbolic material (hBN), the dispersion relation of v-HPs and s-HPs in a thin sheet of hyperbolic material can be derived as 42,43 b…”

Coupling Between Hyperbolic Phonon Polaritons Excited in Two Ultrathin Hexagonal Boron Nitride Sheets

“…The electric field is normalized to the electric field at the upper air/hBN interface, and the method is transfer matrix method. [33] The electric field exponentially decays in the air, while it is enhanced in the hBN sheet. Therefore, the distribution of electric field can ensure that modes excited at the air/hBN interfaces are not surface modes.…”

Modulation of Casimir Force between Graphene-Covered Hyperbolic Materials

“…Hexagonal boron nitride (hBN) is a natural HM with hyperbolic responses in the infrared frequency range [47]. Hyperbolic phonon polaritons can be supported by hBN, which has been thoroughly investigated [48], and as microfabrication technology develops, artificial HMs with hyperbolic responses in specific frequency bands can be constructed. In general, alternative metal-dielectric layered structures [49] or a lattice of nanowires embedded in a dielectric matrix [46] can be used to realize artificial HMs.…”