A5071494815- Plasmonic and Surface Plasmon Research
- Thermal Radiation and Cooling Technologies
- Mechanical and Optical Resonators
- Metamaterials and Metasurfaces Applications
- Photonic and Optical Devices
- Strong Light-Matter Interactions
- Terahertz technology and applications
- Transition Metal Oxide Nanomaterials
- Advanced Fiber Laser Technologies
- Statistical Methods and Inference
- Neural Networks and Reservoir Computing
- Optical Network Technologies
- Photonic Crystals and Applications
- Probabilistic and Robust Engineering Design
- Knowledge Societies in the 21st Century
- Statistical and numerical algorithms
- Nanowire Synthesis and Applications
- Photoacoustic and Ultrasonic Imaging
- Advanced Optical Sensing Technologies
- Gas Sensing Nanomaterials and Sensors
- Semiconductor Quantum Structures and Devices
- Near-Field Optical Microscopy
- Control Systems and Identification
- Nanotechnology research and applications
Universidad de Oviedo
2019-2025
Nanomaterials and Nanotechnology Research Center
2019-2025
Center for Biomolecular Nanotechnologies
2024-2025
Italian Institute of Technology
2024-2025
Fritz Haber Institute of the Max Planck Society
2023-2024
Recent discoveries have shown that, when two layers of van der Waals (vdW) materials are superimposed with a relative twist angle between them, the electronic properties coupled system can be dramatically altered. Here, we demonstrate that similar concept extended to optics realm, particularly propagating phonon polaritons–hybrid light-matter interactions. To do this, fabricate stacks composed twisted slabs vdW crystal (α-MoO3) supporting anisotropic polaritons (PhPs), and image propagation...
Abstract The biaxial van der Waals semiconductor α‐phase molybdenum trioxide (α‐MoO 3 ) has recently received significant attention due to its ability support highly anisotropic phonon polaritons (PhPs)—infrared (IR) light coupled lattice vibrations—offering an unprecedented platform for controlling the flow of energy at nanoscale. However, fully exploit extraordinary IR response this material, accurate dielectric function is required. Here, α‐MoO reported by modeling far‐field polarized...
Anisotropic crystals have recently attracted considerable attention because of their ability to support polaritons with a variety unique properties, such as hyperbolic dispersion, negative phase velocity, or extreme confinement. Particularly, the biaxial crystal $\alpha$-MoO$_3$ has been demonstrated phonon polaritons, light coupled lattice vibrations, in-plane anisotropic propagation and unusually long lifetime. However, lack theoretical studies on electromagnetic modes in slabs impedes...
Abstract Electromagnetic field confinement is crucial for nanophotonic technologies, since it allows enhancing light–matter interactions, thus enabling light manipulation in deep sub‐wavelength scales. In the terahertz (THz) spectral range, radiation conventionally achieved with specially designed metallic structures—such as antennas or nanoslits—with large footprints due to rather long wavelengths of THz radiation. this context, phonon polaritons—light coupled lattice vibrations—in van der...
Abstract Refraction between isotropic media is characterized by light bending towards the normal to boundary when passing from a low- high-refractive-index medium. However, refraction anisotropic more exotic phenomenon which remains barely investigated, particularly at nanoscale. Here, we visualize and comprehensively study general case of electromagnetic waves two strongly (hyperbolic) media, do it with use nanoscale-confined polaritons in natural medium: α-MoO 3 . The refracted exhibit...
The propagation of anisotropic polaritons along previously forbidden directions through a topological transition is demonstrated.
Phonon polaritons (PhPs)—light coupled to lattice vibrations—with in-plane hyperbolic dispersion exhibit ray-like propagation with large wave vectors and enhanced density of optical states along certain directions on a surface. As such, they have raised surge interest, promising unprecedented manipulation infrared light at the nanoscale in planar circuitry. Here, we demonstrate focusing PhPs propagating thin slabs α-MoO3. To that end, developed metallic nanoantennas convex geometries for...
Phonon polaritons (PhPs)─lattice vibrations coupled to electromagnetic fields─in highly anisotropic media display a plethora of intriguing optical phenomena, including ray-like propagation, anomalous refraction, and topological transitions, among others, which have potential for unprecedented manipulation the flow light at nanoscale. However, properties these PhPs are intrinsically dictated by crystal structure host material. Although in-plane can be steered, even canalized, twisting...
Polaritons in strongly anisotropic thin layers have recently captured considerable attention nanophotonics because of their directional propagation at the nanoscale, which offers unique possibilities for nano-optical applications. However, exploiting full potential polaritons requires a thorough understanding properties, including field confinement, energy, and phase direction losses. Here, we provide novel insights into some fundamental aspects biaxial layers. In particular, introduce...
Abstract Phonon polaritons (PhPs) have attracted significant interest in the nano-optics communities because of their nanoscale confinement and long lifetimes. Although PhP modification by changing local dielectric environment has been reported, controlled manipulation PhPs direct polaritonic material itself remained elusive. Here, chemical switching α-MoO 3 is achieved engineering crystal through hydrogen intercalation. The intercalation process non-volatile recoverable, allowing reversible...
Negative reflection occurs when light is reflected toward the same side of normal to boundary from which it incident. This exotic optical phenomenon not only yet be visualized in real space but also remains unexplored, both at nanoscale and natural media. Here, we directly visualize nanoscale-confined polaritons negatively reflecting on subwavelength mirrors fabricated a low-loss van der Waals crystal. Our near-field nanoimaging results unveil an unconventional broad tunability polaritonic...
Abstract Polariton canalization is characterized by intrinsic collimation of energy flow along a single crystalline axis. This optical phenomenon has been experimentally demonstrated at the nanoscale stacking and twisting van der Waals (vdW) layers α-MoO 3 , combining graphene, or fabricating an h-BN metasurface. However, these material platforms have significant drawbacks, such as complex fabrication high losses in case metasurfaces. Ideally, it would be possible to canalize polaritons...
Canalization is an optical phenomenon that enables unidirectional light propagation without predefined waveguiding designs. Recently demonstrated using phonon polaritons in twisted van der Waals (vdW) layers of α-MoO 3 , it offers unprecedented possibilities for controlling light-matter interactions at the nanoscale. However, practical applications have been hindered by complex sample fabrication stacks. In this work, we introduce a previously unexplored canalization single-thin vdW layer...
The confinement of electromagnetic radiation to subwavelength scales relies on strong light-matter interactions. In the infrared (IR) and terahertz (THz) spectral ranges, phonon polaritons are commonly employed achieve extremely subdiffractional light confinement, with much lower losses as compared plasmon polaritons. Among these, hyperbolic in anisotropic materials offer a highly promising platform for which, however, typically plateaus at values {\lambda}0/100, {\lambda}0 being free-space...
Terahertz (THz) electromagnetic radiation is key to access collective excitations such as magnons (spins), plasmons (electrons), or phonons (atomic vibrations), thus bridging topics between optics and solid-state physics. Confinement of THz light the nanometer length scale desirable for local probing in low-dimensional systems, thereby circumventing large footprint inherently low spectral power density far-field radiation. For that purpose, phonon polaritons (PhPs) anisotropic van der Waals...
The terahertz (THz) frequency range is key to studying collective excitations in many crystals and organic molecules. However, due the large wavelength of THz radiation, local probing these smaller crystalline structures or few-molecule arrangements requires sophisticated methods confine light down nanometer length scale, as well manipulate such a confined radiation. For this purpose, recent years, taking advantage hyperbolic phonon polaritons (HPhPs) highly anisotropic van der Waals (vdW)...
Abstract The vast repository of van der Waals (vdW) materials supporting polaritons offers numerous possibilities to tailor electromagnetic waves at the nanoscale. development twistoptics—the modulation optical properties by twisting stacks vdW materials—enables directional propagation phonon (PhPs) along a single spatial direction, known as canalization. Here we demonstrate complementary type reporting visualization unidirectional ray (URPs). They arise naturally in twisted hyperbolic with...
Optical nanoantennas are of great importance for photonic devices and spectroscopy due to their capability squeezing light at the nanoscale enhancing light-matter interactions. Among them, made polar crystals supporting phonon polaritons (phononic nanoantennas) exhibit highest quality factors. This is low optical losses inherent in these materials, which, however, hinder spectral tuning dielectric nature. Here, active passive ultranarrow resonances phononic realized over a wide range (≈35...
Phonon polaritons (PhPs), light coupled to lattice vibrations, in the highly anisotropic polar layered material molybdenum trioxide (α-MoO3) are currently focus of intense research efforts due their extreme subwavelength field confinement, directional propagation, and unprecedented low losses. Nevertheless, prior has primarily concentrated on exploiting squeezing steering capabilities α-MoO3 PhPs, without inquiring much into dominant microscopic mechanism that determines long lifetimes,...
The Functional Linear Model with Response (FLMFR) is one of the most fundamental models to assess relation between two functional random variables. In this paper, we propose a novel goodness-of-fit test for FLMFR against general, unspecified, alternative. statistic formulated in terms Cram\'er-von Mises norm over doubly-projected empirical process which, using geometrical arguments, yields an easy-to-compute weighted quadratic norm. A resampling procedure calibrates through wild bootstrap on...
Layered materials in which individual atomic layers are bonded by weak van der Waals forces (vdW materials) constitute one of the most prominent platforms for research. Particularly, polar vdW crystals, such as hexagonal boron nitride (h-BN), alpha-molybdenum trioxide (α-MoO3) or alpha-vanadium pentoxide (α-V2O5), have received significant attention nano-optics, since they support phonon polaritons (PhPs)―light coupled to lattice vibrations― with strong electromagnetic confinement and low...
The emergence of a vast repository van der Waals (vdW) materials supporting polaritons - light coupled to matter excitations offers plethora different possibilities tailor electromagnetic waves at the subwavelength-scale. In particular, development twistoptics study optical properties twisted stacks vdW allows directional propagation phonon (PhPs) along single spatial direction, which has been coined as canalization. Here we demonstrate complementary type nanoscale unidirectional that...