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Hybrid polariton evolution in graphene/α-MoO3 heterostructure as a function of frequency and Fermi energy. (a-d) Simulated electric field spatial distribution (top panels) and corresponding colorplots IFCs (bottom panels) of hybrid polaritons at high-frequency bands for Fermi energies of 0.1, 0.2, 0.3, and 0.4 eV, respectively. (e-h) Electric field spatial distribution (top panels) and the corresponding colorplots IFCs at the low-frequency band.
Source publication
Electromagnetic field confinement is significant in enhancing light-matter interactions as well as in reducing footprints of photonic devices especially in Terahertz (THz). Polaritons offer a promising platform for the manipulation of light at the deep sub-wavelength scale. However, traditional THz polariton materials lack active tuning and anisotr...
Contexts in source publication
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... study in more detail the polariton-coupling features as a function of Fermi energy in graphene/α-MoO3 heterostructures, we calculate the Ez distribution at the crossingpoint frequencies in Figure 4. When the graphene Fermi energy is 0.1 eV, the polariton coupling should be enhanced at 11.6 THz; the near-field Ez distribution and the corresponding FFT are shown in Figure 5a. It is found that the near-field distribution To study in more detail the polariton-coupling features as a function of Fermi energy in graphene/α-MoO 3 heterostructures, we calculate the E z distribution at the crossing-point frequencies in Figure 4. ...
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... is found that the near-field distribution To study in more detail the polariton-coupling features as a function of Fermi energy in graphene/α-MoO 3 heterostructures, we calculate the E z distribution at the crossing-point frequencies in Figure 4. When the graphene Fermi energy is 0.1 eV, the polariton coupling should be enhanced at 11.6 THz; the near-field E z distribution and the corresponding FFT are shown in Figure 5a. It is found that the near-field distribution features elliptic wavefronts with long axes centered along the crystallographic directions [100], which is significantly different from that typically observed in bare graphene or α-MoO 3 (Figure 2). ...
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... the Fermi energy is 0.1 eV, the polaritons are strongly hybridized at 10.1 THz, and the hybrid polaritons propagate in a specific direction (canalization regime). Note that the IFC exhibits a strong flattening along the [001] direction, explaining the canalization of hybrid polaritons along this direction (Figure 5e). When the Fermi energy increases to 0.2 eV, the near-field distribution features elliptic wavefronts with long axes centered along the crystallographic directions of [001], which is opposite to that for the high-frequency band. ...
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... the Fermi energy is 0.1 eV, the polaritons are strongly hybridized at 10.1 THz, and the hybrid polaritons propagate in a specific direction (canalization regime). Note that the IFC exhibits a strong flattening along the [001] direction, explaining the canalization of hybrid polaritons along this direction (Figure 5e). When the Fermi energy increases to 0.2 eV, the near-field distribution features elliptic wavefronts with long axes centered along the crystallographic directions of [001], which is opposite to that for the high-frequency band. ...
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... p , r j and λ p represent the polariton damping rate, distance between the nanostructure edge and dipole tip, and the polariton wavelength, respectively. In simulations the amplitude of the dipole-launched polariton wave E 0 was set to 1 and the damping rate γ p to 0.4 eV, whereas the polariton wavelength λ p is set based on Figure 5. Reflectivity was assumed to be 1, and 1.5π was used for the phase shift of the polariton wave [26]. ...
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Citations
... Strongly anisotropic materials can support hyperbolic phonon polaritons (HPhPs) that exhibit a hyperbolic dispersion whose permittivity tensor posses both positive and negative principal components [2,[7][8][9]. There has been significant progress in natural vdW crystal and heterostructures, which are characterized by an anisotropic polaritonic response, leading to elliptical, hyperbolic, or biaxial polaritonic dispersions [10,11]. Different polaritonic modes in vdW materials have been discovered, such as plasmon polaritons in graphene, exciton polaritons in molybdenum diselenide (MoSe 2 ), phonon polaritons in hexagonal boron nitride (hBN), and MoO 3 [12][13][14][15][16]. ...
Controlling the twist angle between double stacked van der Waals (vdW) crystals holds great promise for nanoscale light compression and manipulation in the mid-infrared (MIR) range. A lithography-free geometry has been proposed to mediate the coupling of phonon polaritons (PhPs) in double-layers of vdW α-MoO3. The anisotropic hyperbolic phonon polaritons (AHPhPs) are further hybridized by the anisotropic substrate environment of magneto-optic indium arsenide (InAs). The AHPhPs can be tuned by twisting the angle between the optical axes of the two separated layers and realize a topological transition from open to closed dispersion contours. Moreover, in the presence of external magnetic field, an alteration of the hybridization of PhPs will be met, which enable an efficient way for the control of light-matter interaction at nanoscale in the MIR region.
