There are two widely accepted restrictions on the application of the discrete dipole approximation (DDA) in the study of light scattering by particles comparable to the wavelength: (1) when considering dielectric particles, the size of the cells must satisfy the condition kd|m|<0.5, where k is the wavenumber, d is the size of the cells, and m is the complex refractive index of the constituent m...

Research on the optical properties of black carbon (BC) aerosols is highly important for investigating global climate change. A general inhomogeneous particle superposition model developed. Inhomogeneous particles with arbitrary shapes can be constructed by this model. BC core-shell, spherical, ellipsoid, and irregular coating models are established to explore impact shape their properties. The...

   This article describes a study, using numerical simulation, of the optical properties of nano particles as a function of their size. Many methods introduced to simulate and calculate the interaction of light and particle, such as Mie analysis, boundary element and finite element methods. The Discrete Dipole Approximation (DDA), wherein a target geometry is modeled as a ...

We have developed a numerical Regolith Radiative Transfer (RRT) model based on the Discrete-Dipole Approximation (DDA), which iteratively solves the exact wave equations for a granular target in response to an incident plane wave and mutual interactions between all component grains. We extend the traditional DDA approach in two ways: the DDA target is laterally replicated using periodic boundar...

Red-shifting of the optical absorption spectra of aggregates of gold nanoparticles by dipole-dipole interactions is of considerable interest, both for theoretical reasons and because the phenomenon can be potentially exploited in various applications. A convenient and practical way to control the effect is to assemble the aggregated ensemble of n gold nanoparticles on the outer surface of large...

[1] The millimeter wavelength radar backscattering properties at 94 GHz for six nonspherical ice crystals, which include hexagonal column, hollow, plate, bullet rosette, aggregate, and droxtal with 46 maximum dimensions ranging from 2 to 10,500 mm, are investigated using the discrete dipole approximation (DDA) method and Lorenz-Mie theory. It is found that the radar backscattering cross section...

In this article, we investigate the Surface-Enhanced Raman Scattering (SERS) efficiency of methylene blue (MB) molecules deposited on gold nanostripes which, due to their fabrication by electron beam lithography and thermal evaporation, present various degrees of crystallinity and nanoscale surface roughness (NSR). By comparing gold nanostructures with different degrees of roughness and crystal...

The plasmonic properties of single silver triangular nanoprisms are investigated using dark-field optical microscopy and spectroscopy. Two distinct localized surface plasmon resonances (LSPR) are observed. These are assigned as in-plane dipolar and quadrupolar plasmon excitations using electrodynamic modeling based on the discrete dipole approximation (DDA). The dipole resonance is found to be ...

Spatial control of carrier density is critical for engineering and exploring the interactions of localized surface plasmon resonances (LSPRs) in nanoscale semiconductors. Here, we couple in situ infrared spectral response measurements and discrete dipole approximation (DDA) calculations to show the impact of axially graded carrier density profiles on the optical properties of mid-infrared LSPRs...