A5027520790- Plasmonic and Surface Plasmon Research
- Gold and Silver Nanoparticles Synthesis and Applications
- Metamaterials and Metasurfaces Applications
- Photonic and Optical Devices
- Advanced Fiber Laser Technologies
- Photonic Crystals and Applications
- Orbital Angular Momentum in Optics
- Nonlinear Optical Materials Studies
- Graphene research and applications
- Mechanical and Optical Resonators
- Topological Materials and Phenomena
- Advanced Antenna and Metasurface Technologies
- Spectroscopy and Quantum Chemical Studies
- Thermal Radiation and Cooling Technologies
- Copper-based nanomaterials and applications
- Carbon Nanotubes in Composites
- Optical Network Technologies
- Nonlinear Photonic Systems
- Photoacoustic and Ultrasonic Imaging
- Photorefractive and Nonlinear Optics
- Diamond and Carbon-based Materials Research
- Quantum Dots Synthesis And Properties
- nanoparticles nucleation surface interactions
- Optical and Acousto-Optic Technologies
- Surface and Thin Film Phenomena
King's College London
2018-2024
London Centre for Nanotechnology
2018-2024
Lomonosov Moscow State University
2011-2015
Optical metasurfaces are thin-layer subwavelength-patterned structures that interact strongly with light. Metasurfaces have become the subject of several rapidly growing areas research, being a logical extension field metamaterials towards their practical applications. demonstrate many useful properties metadevices engineered resonant electric and magnetic optical responses combined low losses structures. Here we introduce basic concepts this research stem from earlier studies...
properties of the optical surface plasmons in microwave and terahertz frequencies using subwavelength artificial structures to construct negative permittivity.The spoof also benefit from realization ultrathin corrugated metallic strips [14], as they are compatible with printed circuit boards (PCBs) integrated technologies.Since propagating localized were experimentally realized PCBs 2013 2014 [14, 15], this area flourishes prospective applications emerging circuits, sensing, wireless...
Abstract Applications in photodetection, photochemistry, and active metamaterials metasurfaces require fundamental understanding of ultrafast nonthermal thermal electron processes metallic nanosystems. Significant progress has been recently achieved synthesis investigation low-loss monocrystalline gold, opening up opportunities for its use ultrathin nanophotonic architectures. Here, we reveal differences hot-electron thermalisation dynamics between polycrystalline (down to 10 nm thickness)...
Optical second harmonic generation (SHG) is studied from multilayer graphene films in the presence of DC electric current flowing sample plane. Graphene layers are manufactured by chemical vapour deposition (CVD) technique and deposited on an oxidised Si(001) substrate. SHG intensity layer found to be negligible absence current, while it increases dramatically with application current. The current-induced change rises linearly amplitude changes its sign under reversal direction opposite....
We study, both experimentally and theoretically, the second-order nonlinear response from resonant metasurfaces composed of metal–dielectric nanodisks. demonstrate that by exciting optical modes composite nanoparticles we can achieve strong enhancement second-harmonic signal metasurface. By employing a multipole expansion method for generated radiation, show observed SHG is due to magnetic dipolar electric quadrupolar
Abstract Light absorption near a surface of conductive materials and nanostructures leads to the excitation nonequilibrium, high-energy charge carriers: electrons above Fermi level or holes below it. When remaining inside material, these so-called hot carriers result in nonlinear, Kerr-type, optical effects important for controlling light with light. They can also transfer into surroundings nanostructures, resulting photocurrent, they interact adjacent molecules media, inducing photochemical...
Ultrafast nonlinearity, which results in modulation of the linear optical response, is a basis for development time-varying media, particular those operating epsilon-near-zero (ENZ) regime. Here, we demonstrate that intraband excitation hot electrons ENZ film second-harmonic resonance shift ∼10 THz (40 nm) and generation (SHG) intensity changes >100% with only minor (<1%) transmission. The 10-fold enhanced by plasmonic metasurface coupled to film, allowing ultrafast circularly polarized SHG....
Abstract Understanding and optimising the mechanisms of generation extraction hot carriers in plasmonic heterostructures is important for applications new types photodetectors, photochemistry photocatalysis, as well nonlinear optics. Here, we show using transient dynamic measurements that relaxation excited hot-carriers Au/Pt hetero-nanostructures accelerated through transfer pathway from Au, where they are generated, to Pt nanoparticles, which act a hot-electron sink. The influence...
The optically driven acoustic modes and nonlinear response of plasmonic nanoparticles are important in many applications, but strongly resonant, which restricts their excitation to predefined wavelengths. Here, we demonstrate that multilayered spherical hetero-nanoparticles, formed by alternating layers gold silica, provide a platform for broadband optical from visible near-infrared They also act as tunable optomechanical system with mechanically decoupled different can be selectively...
Nonlinear processes are at the core of many optical technologies whose further development require optimized materials suitable for nanoscale integration.Here we demonstrate emergence a strong bulk second-order nonlinear response in plasmonic nanorod composite comprised centrosymmetric materials.We develop an effective-medium description underlying physics, compare its predictions to experimental results, and analyze limits applicability.We tunable generation p-polarized second-harmonic...
The dynamics of phonon modes in thin flakes topological insulator ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ has been studied using transient optical second-harmonic spectroscopy. Using the surface sensitivity generation, excitation and a family are observed with response dependent on polarization. Three coherent modes, inaccessible previous linear time-resolved measurements, were detected nonlinear dynamic response. A symmetry-allowed mode identified symmetry selectivity second-order...
Excited carrier dynamics in plasmonic nanostructures determines many important optical properties such as nonlinear response and photocatalytic activity. Here it is shown that mesoscopic covellite nanocrystals with low free-carrier concentration exhibit a much faster relaxation than traditional materials. A nonequilibrium hot-carrier population thermalizes within first 20 fs after photoexcitation. decreased thermalization time compared to bulk consistent the reduced Coulomb screening...
The coherent oscillations of mobile charge carriers near the surface good conductors-surface plasmons-are been exploited in many applications information technologies, clean energy, high-density data storage, photovoltaics, chemistry, biology, medicine and security. Light can be coupled to plasmons trapped interface between a metal an adjacent material. This leads nanoscale confinement light, impossible by any other means, related electromagnetic field enhancement. Microscopic electron...
We present the experimental studies on optical second-harmonic generation from nanostructures exhibiting magnetic dipole resonances in visible spectral range. "Nanosandwiches" of composition Au/MgF(2)/Au with average disk diameter 140 nm are packed a square lattice period 400 nm. show that at normal incidence, intensity (SH) wave generated by array increases an order magnitude as excitation wavelength approaches magnetic-dipole resonance, while phase SH experiences shift up to 330°. Based...
Plasmonic nanostructures have demonstrated significant potential for engineering the intensity and polarization state of light with further opportunities to actively manipulate them by external stimulation using nonlinear effects. metamaterials composed arrays vertically oriented metallic nanorods shown a dynamically tunable optical response based on change electron temperature. The modulation properties is particularly pronounced in epsilon-near-zero regime can be enhanced nonlocal Here, we...
Incoherent optical second harmonic generation (SHG) is studied from series of multilayer graphene samples various thickness manufactured by chemical vapor deposition technique and deposited over 150 μm thick glass slides. Two different values the correlation lengths are obtained linear SHG indicatrices reveal existence two types scatterers. The first one associated with homogeneous areas, while originates wrinkles at interdomain boundaries. Second imaging microscopy used to map distribution...
We demonstrate enhancement of second-harmonic generation efficiency in resonant nanostructures supporting optically induced magnetic response. This is achieved through simultaneous excitation electric and multipoles at the wavelength their constructive interference.
Realizing ultrafast optical control of materials is imperative for advancing the field information processing, nonlinear optics, and time-varying materials. Noble metal-based plasmonics has provided many platforms achieving switching, using strong local enhancement offered by plasmonic resonances free-electron nonlinearity. However, switching times in such systems are traditionally constrained relaxation photoexcited hot electrons. In this study, we investigate an interplay between electron...
Photonic skyrmion and meron lattices are structured light fields with topologically protected textures, analogous to magnetic skyrmions merons. Here, we report the theoretical existence of mixed quasicrystals in an evanescent optical field. Topological quasiperiodic tilings even odd point group symmetries demonstrated both electric field spin angular momentum. These contain merons N\'eel-type topology. Interestingly, agreement observations arrangements carbon nanoparticles water driven by...
Manipulating intensity, phase and polarization of the electromagnetic fields on ultrafast timescales is essential for all-optical switching, optical information processing development novel time-variant media. Noble metal based plasmonics has provided numerous platforms switching control, enabled by strong local field enhancement, artificially engineered dispersion Kerr-type free-electron nonlinearities. However, precise control over times spectrum remains challenging, commonly limited...