Tunable polaritonic metasurface absorbers in mid-IR based on hexagonal boron nitride and vanadium dioxide layers

Abstract

Here, a metasurface absorber with switchable spectral response is proposed and discussed. The device is constructed by combining a phase change material (vanadium dioxide, VO 2 ) and a naturally hyperbolic materials (hexagonal boron nitride, hBN), utilizing surface plasmon polaritons (SPPs) and surface phonon polaritons (SPhPs), respectively, at different thermal conditions in the same system. Specifically, we take advantage of the excitation of SPhP in hBN below the VO 2 critical temperature (T < T c ) and SPP from VO 2 layers at higher temperatures (T > T c ), to switch between narrowband nearperfect absorption at ~7.2 μm to broadband absorption at 8-12 μm. It is shown that SPPs and SPhPs can be excited, respectively, by controlling the temperature, offering new opportunities in designing tunable artificial materials and devices for promising nanophotonics applications.

Polarization Reflector/Color Filter at Visible Frequencies via Anisotropic α‐MoO3

“…No extra device is needed to achieve polarization dependence properties since the anisotropic optical properties of the proposed devices stem from the inherent anisotropic crystal structure of α‐MoO 3 . Such devices based on 2D vdW α‐MoO 3 or other potentially 2D vdW materials [ 17–19,31,32 ] can enable polarization sensitivity without complex nanofabrication and provide great flexibility and high throughput manufacturing, which paves the way to more versatile metasurfaces and novel integrated optical devices beyond conventional materials and approaches.…”

“…[ 9–13 ] Since the first isolation of graphene, 2D vdW materials have grown into a large family [ 14 ] and now comprise of both high lattice symmetry isotropic materials and anisotropic materials with low lattice symmetry, such as black phosphorus (BP), [ 6,15–17 ] gallium telluride (GaTe) [ 18 ] and hexagonal boron nitride(hBN). [ 19,20 ] Due to the asymmetrical crystal structure in anisotropic 2D vdW materials, they not only possess properties comparable to those of the most studied isotropic graphene, [ 14,21 ] such as a large on/off ratio and high mobility, but also exhibit in‐plane electrical, optical and thermal anisotropic properties. This in‐plane anisotropy leads to richer physics and provides us another degree of freedom for tuning physical properties.…”

Adaptive tuning of infrared emission using VO2 thin films

“…More interestingly, metasurfaces of VO 2 27 in combination with natural hyperbolic polar materials, such as hBN, enable the tuning, manipulation and/or enhancement of optical phonon modes. Nanopatternened metasurfaces have been proposed to tune polaritonic bands of polar material, where the plasmonic coupling is excited in VO 2 above phase transition temperature 28 . The complex pattern of polaritons in hBN have been also experimentally imaged using SNOM measurements from a reconfigurable metasurface where hBN has been transferred on top of a single crystal VO 2 layer 29 .…”

Lithography-free IR polarization converters via orthogonal in-plane phonons in α-MoO3 flakes

“…Hyperbolicity is also the backbone of exceptional optical phenomena such as hyperlensing [13][14][15] , enhanced thermal radiation 16,17 , canalization 11 , and negative refraction 18 . Originally hyperbolicity was primarily demonstrated using artificial materials (aka metamaterials) consisting of reflective and transparent domains or dielectrics developed with intricate fabrication methods that rely on periodic sub-wavelength features patterned using laborious lithography techniques 12,[19][20][21][22] . As a result, the geometric quality of the periodic cell and associated fabrication non-idealities, compromises the photonic figures of merit of the devices 23 .…”