We studied the influence of localized surface plasmon resonance (LSPR) sustained by arrays metallic nanoparticles on efficiency surface-enhanced Raman scattering (SERS). found that enhancement originates from excitation LSPR does depend particle shape. Two different shapes were investigated: cylindrical particles, for which maximum occurred a located around 650 nm, and ellipsoidal exhibit strongest SERS signal at 700 nm. These results are compared to an analytical model in quasistatic...

The sub-diffraction imaging of the optical near-field in nanostructures, based on a photochemical technique, is reported. A photosensitive azobenzene-dye polymer spin coated onto lithographic structures and subsequently irradiated with laser light. Photoinduced mass transport creates topographic modifications at film surface that are then measured atomic force microscopy (AFM). AFM images correlate rigorous theoretical calculations intensities for range different nanostructures illumination...

Surface-enhanced Raman spectroscopy (SERS) is now a well-established technique for the detection, under appropriate conditions, of single molecules (SM) adsorbed on metallic nanostructures. However, because large variations SERS enhancement factor surface, only located at positions highest enhancement, so-called hot-spots, can be detected single-molecule level. As result, in all SM-SERS studies so far small fraction, typically less than 1%, are actually observed. This complicates analysis...

We study the importance of an often-overlooked aspect surface-enhanced fluorescence (SEF): spectral profile modification (SPM) that should accompany any plasmon-resonance-mediated enhancement or quenching close to metal surfaces. argue theoretically and demonstrate experimentally under SEF conditions plasmon resonances affect not only intensity (enhancement quenching) but also its profile, sometimes a point where original spectrum may no longer be recognizable as such. Moreover, we modified...

The role of surface plasmon in second harmonic generation from arrays gold nanorod particles excited by femtosecond laser pulses is investigated as a function incident light polarization and irradiation wavelength. In addition to photoluminescence, peak observed found depend on the wavelength fundamental frequency beam. particular, authors similarities between extinction spectra nanoparticles emmitted harmonic. This behavior can be explained resonant excitation localized resonances.

In the presence of oriented smectic liquid crystal defects, hybrid systems nanoparticles/liquid crystals form straight chains nanoparticles length longer than tens micrometers and width equal to one single nanoparticle. The interparticle distance in a chain can be varied between few 1.5 nm, highlighting control optical absorption by light polarization monitored gold nanoparticle concentration.

We have measured the polarization and incident angle dependence of Surface-Enhanced Raman Scattering (SERS) signal a nile blue monolayer adsorbed on flat gold surface. Comparisons with predictions electromagnetic (EM) theory indicate that molecules are predominantly These results provide most direct demonstration concept surface selection rules in SERS, further confirm validity SERS-EM model beyond |E|4-approximation.

The failure of the so-called |E|4 approximation surface-enhanced Raman scattering (SERS) electromagnetic (EM) enhancement factor is demonstrated experimentally using arrays highly uniform gold nanoparticles specially designed for this purpose. This first unpolarized detection, and interpretation results then becomes evident by studying case polarized detection. These provide, at same time, a clear experimental verification generalized EM theory SERS beyond (Chem. Phys. Lett. 2006, 423, 63)....

Herein, we report the variation of localized surface plasmon resonance (LSPR) gold nanoparticle (NP) arrays covered by poly(3,4-ethylenedioxythiophene) (PEDOT) as a function electronic state polymer. Giant shifts and fine-tuning LSPR NPs surrounded PEDOT/sodium docecyl sulfate have been achieved. The color variations plasmonic/conducting polymer (CP) devices are given not only changes optical properties CP upon doping but also close synergy NP. Such systems can considerably extend field...

Ocean warming (OW) and marine heatwaves (MHWs) rapidly transform ecosystems, especially when they impact keystone or foundation species. Foundation species such as kelps, fucoids corals are highly sensitive to heat stress, which threatens the future of temperate seaweed forests tropical reefs. However, functioning resilience these systems also relies on less conspicuous coralline algae, whose thermal tolerances have gone largely untested. Here, we examined sensitivity four algal morphotypes...

In this paper, we report on the observation of multipolar surface plasmon excitation in lithographically designed gold nanotriangles, investigated by means far-field extinction microspectroscopy wavelength range 400-1000 nm. Several bands are observed visible and near infrared regions when increasing side length triangles. The assignment these peaks to successive in-plane modes is supported calculations using discrete dipole approximation method. We show that lowest three excitations clearly...

Second-harmonic generation from single gold elliptical nanoparticles is experimentally investigated by a nonlinear scanning near-field optical microscope (SNOM). The response found to be directly related local surface plasmon resonances and particle morphology. combined analysis of linear second-harmonic SNOM images provides discrimination among different light extinction behaviors, not achievable just with techniques. polarization state the emitted second harmonic also investigated,...

Incorporation of catalytically active materials into plasmonic metal nanostructures can efficiently merge the reactivity and energy harvesting abilities both types for visible light photocatalysis. Here we explore influence electromagnetic hotspots in ability core-shell colloidal structures to induce chemical transformations. For this study, developed a synthetic strategy fabrication Au nanoparticle (NP) trimers aqueous solution through fine controlled galvanic replacement between Ag...

Metallic nanoparticle solutions are routinely characterized by measuring their extinction spectrum (with UV–vis spectroscopy). Theoretical predictions such as Mie theory for spheres can then be used to infer important properties, particle size and concentration. Here we highlight the benefits of not only (the sum absorption scattering) but also (which excludes routine characterization metallic nanoparticles. We use an integrating sphere-based method measure combined extinction–absorption...

We present experimental results obtained with a cryogenically cooled, high-resolution x-ray spectrometer based on 141 μm×141 μm Nb-Al-Al2O3-Al-Nb superconducting tunnel junction (STJ) detector in demonstration experiment. Using monochromatized synchrotron radiation we studied the energy resolution of this energy-dispersive for soft x rays energies between 70 and 700 eV investigated its performance at count rates up to nearly 60 000 cps. At several 100 cps achieved an 5.9 (FWHM) electronic...

Control of the optical properties metallic nanoparticles (NP) is realized using an electrochemical switch consisting a thin layer conducting polymer (CP). It shown that quenching localized surface plasmon (LSP) sustained by oblate particles depends frequency LSP resonance. This effect attributed to variation CP dielectric function with wavelength. As consequence, prolate arrays show total resonance along major axis whereas modulation and moderate damping are observed minor axis. Combining...

In this article, we investigate the Surface-Enhanced Raman Scattering (SERS) efficiency of methylene blue (MB) molecules deposited on gold nanostripes which, due to their fabrication by electron beam lithography and thermal evaporation, present various degrees crystallinity nanoscale surface roughness (NSR). By comparing nanostructures with different crystallinity, show that NSR has a strong effect SERS intensity MB probe molecules. particular, features lithographic structures significantly...

We report a self-developing anisotropic gold/polymer hybrid nanosystem that precisely places dye molecules at the plasmonic hotspot of metal nanostructures for sensing and photonics applications. Unlike conventional molecule–particle configurations, (AHN) introduces an spatial distribution dye-containing active medium. This allows us to overlap near-field with medium rule out contribution from background molecules. effect selectively highlights optical response interest, is, located...

In this article, we aim to investigate the sensitivity of regular arrays hybrid plasmonic nanostructures variations in properties local environment (temperature, refractive index, polymer thickness), context sensing and active applications. A proper description characterization such systems is indeed essential order provide designed criteria for efficient stimuli-responsive devices. As an ideal model, introduce a novel kind core–shell system made lithographic gold nanorods (GNRs), coated by...

We show that the study of gold nanoparticle self-assemblies induced by a liquid crystal matrix reveals intimate distorted structure existing prior to nanoparticles' incorporation. also how this controls spacing between nanoparticles in self-assemblies. have created hybrid films cholesteric (CLC) and nanoparticles, CLC being deformed competing anchorings at its two interfaces. Whereas previous results evidenced formation only slightly anisotropic clusters for large (diameter 20 nm), we now...

Photobleaching is a widespread problem in any optical study or application involving fluorophores and particularly acute the context of single-molecule detection. Fluorophores adsorbed on metallic nanostructures are not immune to this problem, but little effort has been devoted understanding how photobleaching modified surfaces if additional mechanisms involved. Here, we tackle issue both theoretically experimentally. We present model accounting for modification standard...