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![In‐plane HPhPslaunched from the flake edge and nanowire. a) 3C‐SiC NW/ α‐MoO3 device schematic in a s‐SNOM. Note the free‐space IR beam and the oscillating metallic AFM tip are artistically showing in the schematic. In practice, the IR beam has a beam spot on the order of the measured α‐MoO3 flake at the laser working frequency. 3C‐SiC NW is placed in the direction along [100] (x) direction of α‐MoO3. Red arrow represents the fundamental HPhPs mode (l = 0), which is reflected from the α‐MoO3 flake edge and is only allowed along [001] direction in the spectral region of interest. Green arrow represents the fundamental HPhPs mode launched from the 3C‐SiC NW in the allowed [001] direction. Magenta arrow represents the higher‐order HPhPs mode (l = 1) launched from the NW with much shorter in‐plane polariton wavelength compared with the fundamental mode. b) s‐SNOM mapping of 3C‐SiC NW (diameter: 100 nm)/ α‐MoO3 (thickness: 120 nm) sample at 900 cm⁻¹. c) s‐SNOM mapping of the same 3C‐SiC NW/ α‐MoO3 sample at 930 cm⁻¹. Third‐harmonic amplitude channel (S3) from s‐SNOM mappings is shown in (b) and (c), and scale bar in (b) and (c) is 1 µm. d) Near‐field line profiles extracted from (b) and (c) show polaritons launched from the NW and reflected from flake edge. λp is the polariton wavelength. Full polariton wavelength is exhibiting in the observed polariton fringes for NW launched HPhPs, while half polariton wavelength is exhibiting in the observed polariton fringes for flake edge reflected HPhPs. Line profiles in (d) are normalized and shifted for clarity. e) Phonon polariton dispersion along [001] direction calculated from the imaginary part of the p‐polarized reflection coefficient with the experimental data for HPhPs from flake edge (only fundamental mode observed, l = 0). f) Calculated phonon polariton dispersion with the experimental data for NW launched HPhPs (both fundamental and higher‐order modes observed, l = 0 and l = 1).](publication/369133628/figure/fig1/AS:11431281173187127@1688783952708/In-plane-HPhPslaunched-from-the-flake-edge-and-nanowire-a-3C-SiC-NW-a-MoO3-device.png)
In‐plane HPhPslaunched from the flake edge and nanowire. a) 3C‐SiC NW/ α‐MoO3 device schematic in a s‐SNOM. Note the free‐space IR beam and the oscillating metallic AFM tip are artistically showing in the schematic. In practice, the IR beam has a beam spot on the order of the measured α‐MoO3 flake at the laser working frequency. 3C‐SiC NW is placed in the direction along [100] (x) direction of α‐MoO3. Red arrow represents the fundamental HPhPs mode (l = 0), which is reflected from the α‐MoO3 flake edge and is only allowed along [001] direction in the spectral region of interest. Green arrow represents the fundamental HPhPs mode launched from the 3C‐SiC NW in the allowed [001] direction. Magenta arrow represents the higher‐order HPhPs mode (l = 1) launched from the NW with much shorter in‐plane polariton wavelength compared with the fundamental mode. b) s‐SNOM mapping of 3C‐SiC NW (diameter: 100 nm)/ α‐MoO3 (thickness: 120 nm) sample at 900 cm⁻¹. c) s‐SNOM mapping of the same 3C‐SiC NW/ α‐MoO3 sample at 930 cm⁻¹. Third‐harmonic amplitude channel (S3) from s‐SNOM mappings is shown in (b) and (c), and scale bar in (b) and (c) is 1 µm. d) Near‐field line profiles extracted from (b) and (c) show polaritons launched from the NW and reflected from flake edge. λp is the polariton wavelength. Full polariton wavelength is exhibiting in the observed polariton fringes for NW launched HPhPs, while half polariton wavelength is exhibiting in the observed polariton fringes for flake edge reflected HPhPs. Line profiles in (d) are normalized and shifted for clarity. e) Phonon polariton dispersion along [001] direction calculated from the imaginary part of the p‐polarized reflection coefficient with the experimental data for HPhPs from flake edge (only fundamental mode observed, l = 0). f) Calculated phonon polariton dispersion with the experimental data for NW launched HPhPs (both fundamental and higher‐order modes observed, l = 0 and l = 1).
Source publication
Hyperbolic phonon polaritons (HPhPs) are stimulated by coupling infrared (IR) photons with the polar lattice vibrations. Such HPhPs offer low‐loss, highly confined light propagation at subwavelength scales with out‐of‐plane or in‐plane hyperbolic wavefronts. For HPhPs, while a hyperbolic dispersion implies multiple propagating modes with a distribu...
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Violating Kirchhoff's law is generally achieved using patterned nonreciprocal materials, where a guided or polaritonic mode that lies outside the light cone, often via gratings, is excited. Here, we describe how nonreciprocity manifests itself in pattern-free heterostructures. We demonstrate that a resonant mode in a dielectric spacer separating a...
Citations
... The physical arrangement of atoms within calcite allows it to display an extreme form of birefringence in certain frequency ranges, with the material behaving like a metal along one crystallographic direction and like a dielectric along another. This is the definition of hyperbolic behavior [32], which has also been observed in materials like hBN [33][34][35] and MoO 3 [36]. These naturally hyperbolic materials hold great promise for tailored thermal emission where their polaritonic properties can be used in the design of coherent thermal emitters. ...
The polar nature of calcite results in lattice vibrations that can be stimulated through gratings and nanostructures to design spatially and spectrally coherent thermal radiation patterns. In order to obtain optimal design control over such patterned materials, it is first necessary to understand the fundamental emissivity properties of the lattice vibrations themselves. Because calcite is a uniaxial material, when the optic axis (OA) is tilted with respect to the crystal surface, the surface wave solutions to Maxwell’s equations and vibrational modes that are permitted will change due to the crystal’s structural anisotropy. This implies that the OA orientation can play a critical role in dictating which modes can be harnessed when designing a narrowband or angular thermal emitter. Here we explore the angle and polarization dependence of the bulk far-field emissivity of unpatterned calcite with tilted OA. We show that by manipulating the OA orientation via crystallographic off-cut, polarization, and sample rotation, the emissivity at a given frequency can vary by as much as 0.8. These results suggest that, in addition to serving as a basis for modifying the behavior of the relevant phonon polaritons, OA orientation can be used to alter the thermal emission pattern without the need for complex lithographic patterning.
The impact of Artificial Intelligence (AI) is rapidly expanding, revolutionizing both science and society. It is applied to practically all areas of life, science, and technology, including materials science, which continuously requires novel tools for effective materials characterization. One of the widely used techniques is scanning probe microscopy (SPM). SPM has fundamentally changed materials engineering, biology, and chemistry by providing tools for atomic‐precision surface mapping. Despite its many advantages, it also has some drawbacks, such as long scanning times or the possibility of damaging soft‐surface materials. In this paper, we focus on the potential for supporting SPM‐based measurements, with an emphasis on the application of AI‐based algorithms, especially Machine Learning‐based algorithms, as well as quantum computing (QC). It has been found that AI can be helpful in automating experimental processes in routine operations, algorithmically searching for optimal sample regions, and elucidating structure–property relationships. Thus, it contributes to increasing the efficiency and accuracy of optical nanoscopy scanning probes. Moreover, the combination of AI‐based algorithms and QC may have enormous potential to enhance the practical application of SPM. The limitations of the AI‐QC‐based approach were also discussed. Finally, we outline a research path for improving AI‐QC‐powered SPM.
Research Highlights
Artificial intelligence and quantum computing as support for scanning probe microscopy.
The analysis indicates a research gap in the field of scanning probe microscopy.
The research aims to shed light into ai‐qc‐powered scanning probe microscopy.
We analyze, from first-principles calculations, the excitonic properties of monolayer black phosphorus (BP) under strain, as well as of bilayer BP with different stacking registries, as a base platform for the observation and use of hyperbolic polaritons. In the unstrained case, our results confirm the in-plane hyperbolic behavior of polaritons coupled to the ground-state excitons in both mono- and bilayer systems, as observed in recent experiments. With strain, we reveal that the exciton-polariton hyperbolicity in monolayer BP is enhanced (reduced) by compressive (tensile) strain in the zig-zag direction of the crystal. In the bilayer case, different stacking registries are shown to exhibit hyperbolic exciton polaritons with different dispersion, while also peaking at different frequencies. This renders both mechanical stress and stacking registry control as practical tools for tuning physical properties of hyperbolic exciton polaritons in black phosphorus, which facilitates detection and further optoelectronic use of these quasiparticles.
The curved surface has emerged as new research platform for understanding and manipulating novel electromagnetic behaviors in complex media. In this paper, we explore the anisotropic polaritons on the spherical surface based on Maxwell’s fish-eye metric through stereographic projection. Additionally, this phenomenon can be extended to spindle surface by conformal mapping. Our calculations and simulations demonstrate the elliptic and hyperbolic polaritons, excited by an electric dipole on the sphere, will self-focus or focus on the poles on the sphere affected by anisotropic permittivity. Furthermore, we reveal the optical singularity nature of the curved hyperbolic polaritons from the perspective of transformation optics by obtaining the equivalent optical refractive index profiles and the particle potential energy. Based on natural anisotropic materials and metamaterials, the curved polaritons have potential applications in curved surface focusing and chaos regulation. This work not only bridges the transformation optics and anisotropic polaritons at curved surface, but also provides a new route to surface optical field manipulation.
