Publications by authors named "Enrico M Renzi"
Article Synopsis
- The study focuses on creating high-quality optical resonators, essential for technologies like metrology and quantum optics, particularly aiming to achieve extreme temporal coherence at visible wavelengths.* -
- Researchers developed a new type of etch-free metasurface that minimizes defects, successfully demonstrating an impressive ultrahigh-Q resonance in free space, along with a novel spectroscopy technique for detailed analysis.* -
- By integrating a monolayer material, the team achieved highly unidirectional exciton emission without a power density threshold, showcasing potential applications in optical sensing and controlling quantum light sources.*
Polar dielectrics with low crystal symmetry and sharp phonon resonances can support hyperbolic shear polaritons, which are highly confined surface modes with frequency-dependent optical axes and asymmetric dissipation features. So far, these modes have been observed only in bulk natural materials at midinfrared frequencies, with properties limited by available crystal geometries and phonon resonance strength. Here, we introduce hyperbolic shear metasurfaces, which are ultrathin engineered surfaces supporting hyperbolic surface modes with symmetry-tailored axial dispersion and loss redistribution that can maximally enhance light-matter interactions.
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- Structural anisotropy in crystals affects how light travels, especially in the infrared region, where it interacts with phonon polaritons (PhPs), which are quasiparticles formed by light and lattice vibrations.
- Recent research on the monoclinic crystal β-GaO (bGO) reveals that PhPs can exhibit highly asymmetric propagation, which researchers studied using advanced techniques like scanning near-field optical microscopy.
- The study demonstrates that adjusting the laser orientation, the size of nano-antennas, and the frequency of light can significantly influence the behavior of these phonon polaritons, paving the way for practical applications in low-symmetry crystals.
Extreme anisotropy in some polaritonic materials enables light propagation with a hyperbolic dispersion, leading to enhanced light-matter interactions and directional transport. However, these features are typically associated with large momenta that make them sensitive to loss and poorly accessible from far-field, being bound to the material interface or volume-confined in thin films. Here, we demonstrate a new form of directional polaritons, leaky in nature and featuring lenticular dispersion contours that are neither elliptical nor hyperbolic.
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