Resonant light scattering from metal nanoparticles: Practical analysis beyond Rayleigh approximation

Abstract

We propose a simple analytical formula that can quantitatively predict resonant light scattering from metal nanoparticles of arbitrary shape, whose sizes are too large for Rayleigh approximation to be applicable. The formula has been derived as an empirical extension of Mie’s rigorous calculation for light scattering from spheres. It can very well reproduce the experimental characteristics of light scattering from Au nanorods.

Diffractive arrays of gold nanoparticles near an interface: Critical role of the substrate

“…To further discriminate between the two effects-the particle-centers separation from the substrate and the polarizability of the particles-we explore next arrays formed by elongated ellipsoids of increasing aspect ratio, showing that an increase in polarizability drives a transition between suppression and emergence of diffraction features. Within the framework of the dipolar approximation used in our analytical model, we adopt the polarizability prescription developed by Kuwata et al, 33 which provides a good approximation for subwavelength particles of moderate aspect ratio. Figure 5͑a͒ presents results of this model for prolate gold ellipsoids immersed in water.…”

“…The polarizability is derived from Ref. 33. ͑b͒ Reflectance of ellipsoid arrays calculated from the analytical model of Eq.…”

“…[25][26][27][28][29][30][31][32] For the geometrical parameters under consideration, it is reasonable to represent the particles as induced point dipoles, for which we obtain the polarizability ␣ from the first Mie coefficient. 33 In the array, the dipole moment p j at each particle site j satisfies the self-consistent coupled-dipole equation…”

Plasmonics: Localization and guiding of electromagnetic energy in metal/dielectric structures

“…The depolarization field and radiation damping effect can be seen as lowest-order corrections to the quasistatic theory, leading to additional real and imaginary parts of the denominator of the polarizability. A generalization of the quasistatic approach to particles of arbitrary shape has been suggested, with surprisingly good results 17 ͓see Fig. 2͑a͔͒.…”

Optical trapping and manipulation of plasmonic nanoparticles: fundamentals, applications, and perspectives

“…Generalizations of eqn (3) for non-spherical objects, ellipsoids, and spheroids have been proposed. 44,45 Although it is easy to calculate a(u) as shown in eqn (3), there is no easy way to measure it experimentally since one must determine the charge distribution of the entire metal sphere upon light excitation.…”