Study of Optical Properties of Ag Pyramid Nanostructures by Discrete Dipole Approximation Method

In this paper, we investigate optical properties of silver pyramid nanostructures (SPNs) by means of discrete dipole approximation (DDA), when these nanoparticles are embedded into the water. Absorption, scattering and extinction cross-sections of the SPNs were calculated by change of incident wavelength in visible and near infra-red region. Moreover, height, wavelength and full width at half maximum (FWHM) of extinction cross-section peaks (due to plasmon resonances) were studied by change of nanostructure's size and dielectric constant of medium. Our results show that, there are only two peaks of dipole and quadruple modes in this spectrum.