Determination of optical properties of percolated nanostructures using an optical resonator system

Abstract

In this work, methods are introduced to the determination of optical properties of thin silver films and nanostructures. We present an optical resonant system consisting of a mirror, a transparent layer and a thin silver film. The layer sequences and the nanostructure of the thin films are investigated by optical methods consist of reflectance measurements. The structures are analyzed by atomic force microscopy and scanning electron microscopy. The optical properties are determined by modeling the reflectance data. We have found that the growth mechanisms of the silver layer are correlated to its optical properties. It also found that temperature treatments produce isolated particles with a narrow plasmon resonance.

Experimental and theoretical determination of the plasmonic responses and shape distribution of colloidal metallic nanoparticles

“…7(b)) is characterized by two overlapped broad bands centered at 2.05 eV and 2.32 eV. By considering Fröhlich condition (15), these bands are assigned to 0.15 and 0.3 depolarization parameters. In other words, the band centered at 2.32 eV is the optical signature of spherical NPs, while the band centered at 2.05 eV can be assimilated to the L-SPR band of Au nanorods.…”

“…The Maxwell Garnett theory, 12 which is based on the Lorentz local field, is often used to predict the SPR band of monodispersed spherical NPs. [13][14][15][16] This model was recently extended to describe the optical properties of spherical NPs distributed in size by averaging their polarizability. 17,18 However, preparation routes unavoidably conduct to NPs showing a shape distribution which induces drastic changes in the optical properties of NP assembly.…”

Plasmonic and metallic optical properties of Au/SiO2 metal-insulator films

“…However, the variations of the L2 film thickness are more tedious and can be explained by a competition between the lateral and the vertical growth of gold nanostructures. Indeed, as pointed out previously, 7 at the beginning of the deposition, Au adatoms migrate on the SiO 2 surface until they nucleate on other adatoms, resulting in the formation of Au NPs (Film F1) through a Volmer-Weber growth mode. This mode occurs when adatoms are more strongly bounded to each other than with the substrate.…”

“…1 Indeed, depending on their composition, these metal-insulator films (MIFs) can have metallic or insulating behavior. [2][3][4][5][6] Moreover, as reported by several authors, MIFs can exhibit strong plasmonic effects [7][8][9][10] and local electric field enhancement. [11][12][13] Therefore, they can be considered as a building block for nonlinear materials, 14,15 new metamaterial devices, 16 plasmonic sensors, [17][18][19] or transparent screens.…”

“…Once the SiO 2 surface is completely covered, the film thickness takes the same value as the nominal one (film F4) and starts to increase linearly with the deposition time through a Frank-Van der Merwe growth mode. 7 This growth mode occurs when adatoms are strongly bounded to the substrate. This is the case for long deposition time in which the thick gold film can be assimilated to the substrate.…”