Dispersion of nonlinear dielectric function of Au nanoparticles in silica glass

Quantum Beam Center, National Institute for Materials Science, 3-13 Sakura, Tsukuba, Ibaraki, 305-0003, Japan.
Optics Express (Impact Factor: 3.53). 06/2007; 15(10):6010-8. DOI: 10.1364/OE.15.006010
Source: PubMed

ABSTRACT We have investigated wavelength dispersion of photo-induced nonlinear dielectric function of Au nanoparticle materials. Transient transmission and reflection spectra were sequentially measured by the pump-probe method with a femtosecond laser system. The dispersion of real and imaginary parts of the nonlinear dielectric function of Au:SiO(2) nanoparticle material in the vicinity of the surface plasmon resonance was evaluated from these transient spectra with total differential. A local electromagnetic field factor and interband transition in Au nanoparticles directly dominate the dispersion.

Download full-text


Available from: O.A. Plaksin, Apr 25, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Gold nanoparticles have been used since antiquity for the production of red-colored glasses. Contemporarily, it was determined that this color is caused by plasmon resonance, which, additionally, increases the material's nonlinear optical response, allowing for the improvement of numerous optical devices. Interest in silica fibers containing gold na-noparticles has increased recently, aiming at the integration of nonlinear devices with conventional optical fibers. Fabri-cation, however, is challenging due to the high temperatures required for silica processing and fibers with gold nanoparticles were solely demonstrated using sol-gel techniques. We show a new fabrication technique based on standard pre-form/fiber fabrication methods, where nanoparticles are nucleated by heat in a furnace or by laser exposure, with unprec-edented control over particle size, concentration and distribution. Plasmon absorption peaks exceeding 800 dB.m-1, at 514-536nm wavelengths, were observed, indicating higher achievable nanoparticle concentrations than previously report-ed. The measured resonant nonlinear refractive index, (6.75±0.55)×10-15m².W-1, represents an improvement of >50×.
    ACS Applied Materials & Interfaces 12/2014; 7(1). DOI:10.1021/am506327q · 5.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The effects of size quantization on the nonlinear optical response of Ag nanoparticles are experimentally studied by spectroscopic ellipsometry and femtosecond spectroscopic pump-and-probe techniques. In the vicinity of a localized surface-plasmon resonance (2.0–3.5 eV), we have investigated the optical nonlinearity of Ag particles embedded in silica glass for particle diameters ranging from 3.0 to 16 nm. The intrinsic third-order optical susceptibility χ(3) of Ag particles exhibited significant spectral and size dependences. These results are explained as quantum and dielectric confinements and are compared to the results of theoretical quantum finite-size effects calculation for metallic particles. In light of these results, we discuss the contribution of interband transitions to the size dependence of χ(3). Quantum size effects lead to an increase in nonlinearity in small Ag particles.
    Physical Review B 09/2014; 90(12):125417. DOI:10.1103/PhysRevB.90.125417 · 3.66 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The direct observation and characterisation of silver nanoparticles or clusters embedded in a Ag+-activated phosphate glass was demonstrated. Correlations between the isolated Ag+ concentration and X-ray-induced silver species were systematically examined using optical measurements. Evidence of spherical silver nanoparticles or clusters with sizes ranging from 5 to 30nm was obtained from the lattice spacings and from energy dispersive X-ray spectroscopy combined with transmission electron microscopy. Three-dimensional contour plots using combined excitation–emission spectroscopy were also recorded to allow identification of the complicated spectroscopic features of the sample.
    Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 12/2011; 269(23):2814-2818. DOI:10.1016/j.nimb.2011.08.019 · 1.19 Impact Factor