The low-energy cluster beam deposition technique (LECBD) is applied to produce assembled films with hitherto unknown nanostructured morphologies and properties. Neutral clusters having the very low energy gained in supersonic expansion at exit of inert gas condensation-type source are deposited without fragmentation upon impact on substrate. Depending conditions (nature, size flux incident clusters, nature temperature substrate, vacuum conditions), granular nanostructures resulting from...

We report experiments on gold clusters in the size range 2--4 nm, embedded an alumina matrix. The metallic particles are produced with a laser vaporization source and codeposited dielectric vapor as thin film substrate. Our technique allows varying cluster at given metal concentration. These composite materials studied through optical absorption ellipsometric measurements, allowing determination of their complex index refraction. Various complementary techniques provide information about...

The surface plasmon energy of silver clusters is investigated in the framework time-dependent local density approximation. results are good agreement with experimental data on free ${\mathrm{Ag}}_{N}^{+}$ and ${\mathrm{Ag}}_{N}$ embedded solid argon alumina. size effects weak very sensitive to matrix, porosity at interface, cluster charge. It shown that core-electron contribution metal dielectric function mainly responsible for quenching optical response.

The surface phonon-polaritons contribution to the thermal conductivity of a nano thin film silicon dioxide is investigated based on Maxwell equations and Boltzmann transport equation. It shown that: (1) small difference between permittivities substrate superstrate can generate giant propagation lengths therefore remarkably enhances its with respect values obtained for freestanding one. (2) present in broad band frequencies exhibits largest at frequency where absorption energy minimal. (3)...

Plasmonic nanoparticles offer a broad range of functionalities, owing to their ability amplify light in the near-field or convert it into heat. However, ultrafast nonlinear optical response remains too low envisage all-optical high-rate photonic processing applications. Here, we tackle this challenge by coupling localized plasmon mode gold with 1D resonant cavity. Despite nonradiative losses, demonstrate that strong, reversible, and modulation can be achieved. By using pumping fluence less...

Absorption and low-frequency Raman-scattering experiments have been performed on thin films consisting of small silver clusters embedded in a porous alumina matrix. When the Raman excitation wavelength is close to maximum (\ensuremath{\approx}420 nm) Mie band (dipolar surface plasmon resonance) spectra exhibit strong located around 10 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$, which depends cluster diameter D at cluster-size distribution sample according approximate law...

The electron dynamics is studied in silver nanoparticles of different sizes embedded either a silicate glass or porous alumina matrix, using time-resolved optical spectroscopy. femtosecond pump–probe measurements, made under various conditions excitation, reveal that the energy relaxation faster as particle size decreases. For particles with identical and excitation conditions, time found to be for clusters matrix. influence surface acoustic modes heat conductivity matrix on discussed.

The optical properties of nanocomposite materials made matrix-embedded noble metal nanoparticles strongly depend on thermal effects from different origins. We propose a classical model describing the energy exchanges within and between latter surrounding dielectric host subsequent to light pulse absorption. This model, which accounts for interactions neighboring particles, allows us calculate numerically temperature dynamics electrons, lattice matrix as functions particle size, concentration...

Understanding the plasmon coupling between metal nanoparticles under light irradiation remains a challenging issue for optimizing plasmonic devices chemical and biological sensing. Here, optical properties of dense spatially ordered two-dimensional arrays 50 nm gold are investigated in this aim. Microspectrophotometry experiments carried out on square parallel chains, elaborated by electron beam lithography, having different periodicities ranging from 80 to 170 nm. The wavelength, width,...

The ultrafast transient optical response of gold nanorods presents a complex spectral signature that is very sensitive to the nanoparticle aspect ratio. This stems from different electronic contributions photoinduced dynamics metal dielectric function, which modify transverse and longitudinal localized plasmon modes. Here, we analyze physical origins ensembles over whole visible range. Using broadband time-resolved spectroscopy, determine within first picoseconds after pump excitation...

HER2-overexpressing metastatic breast cancers are challenging practice in oncology when they become resistant to anti-HER2 therapies such as trastuzumab. In these clinical situations, HER2-overexpression persists localizations, and can thus be used for active targeting using innovative therapeutic approaches. Functionalized gold nanoparticles with antibody stimulated by near-infrared light induce hyperthermia.Here, hybrid nanoshells were engineered photothermal therapy overcome trastuzumab...

Thermo-optical properties of composite materials consisting noble metal nanoparticles spread in a dielectric host matrix are relevant for various fields fundamental and applied nanosciences. We present calculation these the framework Maxwell-Garnett effective medium model, exemplified by case gold silica. The spectral variations bulk thermo-optical coefficients, including implicitly temperature dependence intra- interband transitions, first extracted from experimental results literature....

Optical properties of copper clusters $3\phantom{\rule{0.5em}{0ex}}\text{to}\phantom{\rule{0.5em}{0ex}}5\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ in diameter, produced by laser vaporization and embedded alumina, are investigated compared to a semi-quantal model [based on time-dependent local-density approximation (TDLDA) density functional theory (DFT)], including the absorption screening ionic core background surrounding matrix. To begin with, experiments show that alumina trapped oxidized if...

A novel one-pot synthesis method to prepare gold nanorods of different aspect ratios using radiolysis is presented. The are synthesized by radiolytic reduction AuIII complexes in a micellar solution formed mixture cationic surfactants (cetyltrimethylammonium bromide and tetraoctylammonium bromide) the presence acetone silver ions. mechanisms formation discussed. can be trapped poly(vinyl alcohol) gel under irradiation. UV−visible absorption spectra nanorod solutions compared with...

The generation of reactive oxygen species by gold nanorods under ultrashort-pulsed irradiation is investigated at the single-nanoparticle level. Near-infrared femtosecond pulses induce production hydroxyl radicals in a hydrogel medium through plasmon-assisted, polarization-controlled, multiphoton process. Three-photon luminescence also observed, allowing potential replacement for photodynamic agents combined with nonlinear imaging properties. As service to our authors and readers, this...

The second order nonlinear response from 4 nm diam gold clusters embedded in an alumina matrix deposited on a pure silica substrate has been recorded as function of the wavelength fundamental incident beam. spectrum exhibits narrow resonance band peaked at 520 result coupling harmonic field with surface plasmon particles. is found to be blueshifted compared bulk, due finite size effects cluster optical properties, already observed linear response. Furthermore, this appears well described...

The third-order nonlinear optical response of noble-metal nanoparticles embedded in a dielectric matrix depends on the particle intrinsic susceptibility ${\ensuremath{\chi}}_{m}^{(3)}$. We propose model which allows one to calculate hot electron contribution ${\ensuremath{\chi}}_{\text{he}}^{(3)}$ ${\ensuremath{\chi}}_{m}^{(3)}$ case gold. This phenomenon stems from modification conduction-electron distribution induced by an excitation, and is significant when picosecond or subpicosecond...

The nonlinear absorption of nanocomposite layers based on ZnO implanted with Cu+ ions an energy 160 keV in implantation doses 10(16) and 10(17) ions/cm2 was investigated. values the coefficient were measured by Z-scan method at a wavelength 532 nm use nanosecond picosecond laser pulses. Possible optical applications these materials are discussed.