Polariton waveguide modes in two-dimensional van der Waals crystals: an analytical model and correlative nano-imaging

Sun, Fengsheng; Huang, Wuchao; Zheng, Zebo; Xu, Ning; Ke, Yu; Zhan, Runze; Chen, Huanjun; Deng, Shaozhi

doi:10.1039/d0nr07372e

Cited by 24 publications

(22 citation statements)

References 48 publications

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“…[3,4] An analytical model was first developed to calculate the in-plane IFC q[ ↔ 𝜀(𝜔), d, 𝜃], of the HPhPs propagating inside a vdW slab of finite thickness (see Note S1, Supporting Information). [36,37] To simplify the discussion, 𝜖 denotes the real part of the permittivity in our following discussion. According to the model calculations, the electromagnetic waves in the hyperbolic vdW slab are dominated by the TM polariton modes with a dispersion relation…”

Section: Resultsmentioning

confidence: 99%

“…An analytical model was first developed to calculate the in‐plane IFC

q [\overset{\leftrightarrow}{ε} (ω), d, θ]

, of the HPhPs propagating inside a vdW slab of finite thickness (see Note S1, Supporting Information). [ 36,37 ] To simplify the discussion, ε denotes the real part of the permittivity in our following discussion. According to the model calculations, the electromagnetic waves in the hyperbolic vdW slab are dominated by the TM polariton modes with a dispersion relation

\begin{matrix} true \\ right \sqrt{\frac{ε_{t}}{ε_{z}}} \sqrt{k_{0}^{2} ε_{z} - q^{2}} d & = & left normalarc normaltan ((), \frac{\sqrt{ε_{t} ε_{z}}}{ε_{normalc}} \frac{\sqrt{q^{2} - k_{0}^{2} ε_{normalc}}}{\sqrt{k_{0}^{2} ε_{z} - q^{2}}}) \\ left + normalarc normaltan ((), \frac{\sqrt{ε_{t} ε_{z}}}{ε_{normals}} \frac{\sqrt{q^{2} - k_{0}^{2} ε_{normals}}}{\sqrt{k_{0}^{2} ε_{z} - q^{2}}}) + M π \end{matrix}

where ε t = ε x cos 2 θ + ε y cos 2 θ ; d is the slab thickness; k 0 is the free‐space wavevector; θ denotes the angle of the propagation direction relative to the x ‐axis, M represents the order of the different TM modes, and ε c and ε s are the dielectric constants for air and the substrate, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Van der Waals Phonon Polariton Microstructures for Configurable Infrared Electromagnetic Field Localizations

et al. 2021

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Polar van der Waals (vdW) crystals that support phonon polaritons have recently attracted much attention because they can confine infrared and terahertz (THz) light to deeply subwavelength dimensions, allowing for the guiding and manipulation of light at the nanoscale. The practical applications of these crystals in devices rely strongly on deterministic engineering of their spatially localized electromagnetic field distributions, which has remained challenging. The polariton interference can be enhanced and tailored by patterning the vdW crystal -MoO 3 into microstructures that support highly in-plane anisotropic phonon polaritons. The orientation of the polaritonic in-plane isofrequency curve relative to the microstructure edges is a critical parameter governing the polariton interference, rendering the configuration of infrared electromagnetic field localizations by enabling the tuning of the microstructure size and shape and the excitation frequency. Thus, the study presents an effective rationale for engineering infrared light flow in planar photonic devices.

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Section: Resultsmentioning

confidence: 99%

“…An analytical model was first developed to calculate the in‐plane IFC

q [\overset{\leftrightarrow}{ε} (ω), d, θ]

\begin{matrix} true \\ right \sqrt{\frac{ε_{t}}{ε_{z}}} \sqrt{k_{0}^{2} ε_{z} - q^{2}} d & = & left normalarc normaltan ((), \frac{\sqrt{ε_{t} ε_{z}}}{ε_{normalc}} \frac{\sqrt{q^{2} - k_{0}^{2} ε_{normalc}}}{\sqrt{k_{0}^{2} ε_{z} - q^{2}}}) \\ left + normalarc normaltan ((), \frac{\sqrt{ε_{t} ε_{z}}}{ε_{normals}} \frac{\sqrt{q^{2} - k_{0}^{2} ε_{normals}}}{\sqrt{k_{0}^{2} ε_{z} - q^{2}}}) + M π \end{matrix}

Section: Resultsmentioning

confidence: 99%

Van der Waals Phonon Polariton Microstructures for Configurable Infrared Electromagnetic Field Localizations

et al. 2021

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“…S5a, S5b, and Note S2 in Supplementary Information). These are typical fingerprints of HPhP waveguide modes, such as those observed in hBN nanostructures 57 and biaxial α-MoO3 flakes 58 . Notably, in the two 1D-PRPs two valleys with narrow linewidths appear around 1000 cm −1 for both polarization conditions.…”

Section: Fabrication Of In-plane Hyperbolic Polariton Tuner and Far-f...mentioning

confidence: 83%

In-plane hyperbolic polariton tuners in terahertz and long-wave infrared regimes

Huang

Folland

Sun

et al. 2022

Preprint

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Development of terahertz (THz) and long-wave infrared (LWIR) technologies is mainly bottlenecked by the limited intrinsic response of traditional materials. Hyperbolic phonon polaritons (HPhPs) of van der Waals semiconductors couple strongly with THz and LWIR radiation. However, the mismatch of photon−polariton momentum makes far-field excitation of HPhPs challenging. Here, we propose an In-Plane Hyperbolic Polariton Tuner and demonstrate a first device responding to direct far-field excitation and giving rise to a unique set of characteristic functions at far-field. Such a device is based on patterned surface directly written on van der Waals semiconductors; here α-MoO3. The resonances are found to strongly rely on in-plane hyperbolic polariton of patterned α-MoO3, exhibiting high quality factors up to 300, and to determine the characteristics of resultant tunable polarization and selection of the wavelength of reflection and transmission and regulation of output intensity. This is important to development of THz and LWIR miniaturized devices.

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“…[59,60] Ultimately, the inherited birefringence of α-MoO 3 can provide a possible method to control the polarization of emission with a simple planar configuration without nanopatterning on the surface. [61][62][63][64][65][66][67][68]…”

Section: Discussionmentioning

confidence: 99%

Ultrathin High Quality‐Factor Planar Absorbers/Emitters Based on Uniaxial/Biaxial Anisotropic van der Waals Polar Crystals

Zhu

Cai

et al. 2021

Advanced Optical Materials

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Tailoring the absorption/emission through nanostructures from broadband to narrowband has attracted increasing attention due to the merits of high efficiency and compactness. However, most of the reported narrowband emitters require either complex fabrication process or thick coating of the suitable materials (~mm). In this paper, by exciting Berreman mode through a combination of Au mirrors and ultra‐thin layers of low‐loss uniaxial/biaxial anisotropic 2D van der Waals polar crystal hBN/α‐MoO3, a narrowband absorption/emission peak is realized in the mid‐infrared region. The measured quality‐factor of Berreman mode for hBN/Au and α‐MoO3/Au structure can reach up to 134 and 164, respectively. The deep subwavelength thickness (~nm) and bilayer architecture simplify the fabrication process. Furthermore, taking advantage of the in‐plane birefringence originating from α‐MoO3, the polarization of the absorbed/emitted radiation can be controlled through this planar configuration. Such ultrathin narrowband absorbers/emitters provide new opportunities for the advancements in thermal sources, infrared sensors, and thermophotovoltaic power generation systems.

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Polariton waveguide modes in two-dimensional van der Waals crystals: an analytical model and correlative nano-imaging

Abstract: Two-dimensional van der Waals (vdW) crystals can sustain various types of polaritons with strong electromagnetic confinements, making them highly attractive for the nanoscale photonic and optoelectronic applications. While extensive experimental...

Cited by 24 publications

References 48 publications

Van der Waals Phonon Polariton Microstructures for Configurable Infrared Electromagnetic Field Localizations

Van der Waals Phonon Polariton Microstructures for Configurable Infrared Electromagnetic Field Localizations

In-plane hyperbolic polariton tuners in terahertz and long-wave infrared regimes

Ultrathin High Quality‐Factor Planar Absorbers/Emitters Based on Uniaxial/Biaxial Anisotropic van der Waals Polar Crystals

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