Total internal reflection microscopy with a multilayered interface: a light scattering model based on a discrete sources method

Palladium Ultra Thin Layer Profiles Evaluation by Evanescent Light

“…In the second row, the effective penetration depth d m approximated by 1 2  is given. Regarding the mechanism of the evanescent wave extraction, many authors [5,6,[10][11][12][13] assume that the molecules dipoles deposited on the planar interface are responsible for the evanescent photons scattered from the deposited layers. The maximum number of dipole molecules per unit volume N a can be estimated by the following equation [14]:…”

“…The specific gravity and atomic masses for a-Au, Indium, and Pd as well as the results obtained from Equation (17) for the number of atoms per unit volume are given in Table 1. As seen in Table 1, the number of molecules per unit volume N a increases from In to a-Au and Pd as does  , thus the number of excited dipoles assumed in the dipole scattering model is approximately proportional to the molecules volume density of the material deposited [11][12][13]. However, we observe that the "effective" scattering cross-section, * sc  , does not follow the  monotonic increase with N a but rather decreases monotonically with the materials molecular weight M. Thus while a higher  value suggests a greater graininess of the material aggregation structure on the surface, * sc  relates to the higher intrinsic evanescent cross section for materials with lower molecular mass.…”

“…The parameter m defined in Equation (7), differs from d given in Equation 2, and represents a characteristic penetration depth of the evanescent field into the nanomaterial deposited above the waveguide [5,6].  (10) Consequently, the normalized light intensity spatial distribution which is the optical response of the CCD camera measuring the evanescent scattered light intensity has the form: (11) We note that in Equation 11 From Equation 11  (12) We showed in [2] that the NIOD of Equation 4is approximately proportional to the average thickness of the imaged zone and also to  , hence using Equation 12one obtains the following ratio for the NIOD i 's and i  :…”

Nanoprofiles evaluation of ZnO thin films by an evanescent light method

“…Various authors assume that the dipoles close to a planar interface can be considered responsible for the nanometer particles scattering from the deposited layers (Eremina et al, ; Fornel, ; Ganic et al, ; Girard, ; Greffet and Carminati, ; Novotny and Hecht, ; Quinten et al, ). The number of dipole atoms per unit volume ( N a ) can be estimated (Ganic et al, ) by the following equation: where N 0 =6.022 × 10 23 [atoms/mol] is the Avogadro number, ρ is the material density in [g/cm 3 ], and M is the atomic mass in [g/mol].…”

Differential evanescent light intensity imaging of nanothin films: simulation of the scattered field

“…Usually, when total internal reflection (TIR) occurs, the deposited material on top of a waveguide scatters the evanescent waves. The scattering behavior of evanescent light by nano-particles and its dependence on their size has already been investigated by the discrete source method [3], which is a computer model for the analysis of evanescent wave scattering by a spherical particle located near a glass prism.…”