We demonstrate experimentally and support by a theoretical analysis an effect of asymmetric spectrum broadening, which results from doping of silver nanoparticles into a heavy-glass matrix, 90(0.5WO3-0.3SbPO4-0.2PbO)-10AgCl. The strong dispersion of the effective nonlinear coefficient of the composite significantly influences the spectral broadening via the self-phase modulation, and leads to a blue upshift of the spectrum. Further extension of the spectrum towards shorter wavelengths is suppressed by a growing loss caused by the plasmon resonance in the silver particles. The red-edge spectral broadening is dominated by the stimulated Raman Scattering.
Photonic crystal fibers doped with silver nanoparticles exhibit the Kerr nonlinearity that can be positive or negative depending on wavelength and vanishes at a specific wavelength. We study numerically how the simultaneous presence of a zero-nonlinearity wavelength (ZNW) and a zero-dispersion wavelength affects evolution of soliton and supercontinuum generation inside such fibers and find a number of unique features. The existence of negative nonlinearity allows soliton formation even in the normaldispersion region of the fiber, and the ZNW acts as a barrier for the Raman-induced red shift of…
Metal-dielectric interfaces of various geometries are fundamental photonic material platforms for surface plasmons. Surface plasmon polaritons and localized surface plasmons are two surface plasmon modes that are excited on planar and curved metal-dielectric interfaces, respectively. Herein, we demonstrate in-situ formation of silver nanoparticles by diffusion at a planar interface between sputter-deposited silver and nitride dielectrics. In one step, we synthesize a nanostructure that exhibits both localized surface plasmon resonances at silver nanoparticles and surface plasmon resonances at …
This study investigated spectral changes in the absorption cross-sections of single strong coupling systems composed of single silver nanoparticle dimers and a few dye molecules during the quenching of surface-enhanced resonant Raman scattering (SERRS). The absorption cross-section was obtained by subtracting the scattering cross-section from an extinction cross-section. The spectral changes in these cross-sections were evaluated using a classical hybridization model composed of a plasmon and a molecular exciton including a molecular multi-level property. The changes in the scattering and exti…
Plasmonic nanoparticles from unconventional materials can improve or even bring some novel functionalities into the disciplines inherently related to plasmonics such as photochemistry or (spectro)electrochemistry. They can, for example, catalyze various chemical reactions or act as nanoelectrodes and optical transducers in various applications. Silver amalgam is the perfect example of such an unconventional plasmonic material, albeit it is well-known in the field of electrochemistry for its wide cathodic potential window and strong adsorption affinity of biomolecules to its surface. In this st…
Comment on "Silver nanoparticle array structures that produce remarkably narrow plasmon lineshapes" [J. Chem. Phys. 120, 10871 (2004)]
在这篇评论中，我讨论了Zou，Janel和Schatz（ZJS）的论文“Silver nanoparticle array structures that produce extremely narrow plasmon line shapes”[J.Chem.Phys.120，10871（2004）]中的两个错误陈述。第一个陈述是关于准静态近似在我早期关于类似主题的工作中的使用，第二个陈述涉及纳米颗粒周期链中辐射弛豫的精确消除的可能性。阐明了准静态近似、偶极子近似和ZJS所采用的Doyle近似[Phys.Rev.B39，9852（1989）]之间的关系。结果表明，辐射弛豫的精确抵消不能发生在特定的几何考虑ZJS。
A spectral technique is applied to evaluate the resonance frequencies of the full retarded scattering from spherical nanoparticles. This approach allows one to unambiguously identify the modes that are responsible of both the peaks and the asymmetric lineshapes of the scattered power spectra. The fundamental differences between the electromagnetic scattering properties of dielectric and metal spheres are discussed. These results are used to investigate the scattering from isolated silicon and silver nanospheres.
Metal nanoparticles are the most frequently used nanostructures in plasmonics. However, besides nanoparticles, metal nanowires feature several advantages for applications. Their elongation offers a larger interaction volume, their resonances can reach higher quality factors, and their mode structure provides better coupling into integrated hybrid dielectric-plasmonic circuits. It is crucial though, to control the distance of the wire to a supporting substrate, to another metal layer or to active materials with sub-nanometer precision. A dielectric coating can be utilized for distance control, …
Bimetallic plasmonic nanoparticles enable tuning of the optical response and chemical stability by variation of the composition. The present numerical simulation study compares Ag-Au alloy, Ag@Au core-shell, and Au@Ag core-shell bimetallic plasmonic nanoparticles of both spherical and anisotropic (nanotriangle and nanorods) shapes. By studying both spherical and anisotropic (with LSPR in the near-infrared region) shapes, cases with and without interband transitions of Au can be decoupled. Explicit comparisons are facilitated by numerical models supported by careful validation and examination o…
The evidence of strong coupling between plasmons and molecular excitons for plasmonic nanoparticle (NP) dimers exhibiting ultra-sensitive surface enhanced resonant Raman scattering is the observation of anti-crossing in the coupled resonance. However, it is not easy to experimentally tune plasmon resonance of such dimers for the observation. In this work, we theoretically investigate the anti-crossing properties of the dimers coated by the thin dye films with thicknesses greater than 0.1 nm and gap distances larger than 1.2 nm according to the principles of classical electromagnetism. The plas…
Few inventions have shaped the world like the incandescent bulb. While Edison used thermal radiation from ohmically heated conductors, some noble metals exhibit "cold" electroluminescence (EL) in percolation films, tunnel diodes, electromigrated nanoparticle aggregates, optical antennae, or scanning-tunnelling microscopy (STM). The origin of this radiation, which is spectrally broad and depends on applied bias, is controversial given the low radiative yields of electronic transitions. Nanoparticle EL is particularly intriguing since it involves localized surface-plasmon resonances with large d…
Ultrabroad resonance of localized plasmon on a nanoparticle coupled with surface plasmon on a nanowire enabling two-photon excited emission via continuous-wave laser
We provide a microscopic approach to describe the onset of radial oscillation of a silver nanoparticle. Using the Heisenberg equation of motion framework, we find that the coupled ultrafast dynamics of coherently excited electron occupation and the coherent phonon amplitude initiate periodic size oscillations of the nanoparticle. Compared to the established interpretation of experiments, our results show a more direct coupling mechanism between the field intensity and coherent phonons. This interaction triggers a size oscillation via an optically induced electron density gradient occurring dir…
