Investigation of Optical Properties of Ellipsoidal Metal Nanoparticles at Different Scales and Dielectric Environments

Plasmonic science has been noticed by researchers, with the increasing development of knowledge and technology in nanometer dimensions. Gold and silver ellipsoidal metal nanoparticles can exhibit unique optical properties due to their ellipsoidal structure with special symmetry and are therefore very suitable options for use in the new generation of optical sensors. Therefore, in this work, the optical properties of gold and silver metal ellipsoidal nanoparticles were simulated in different dielectric environments as well as in different sizes with using the MATLAB program. The results show that with increasing the diameter of the ellipsoidal nanoparticles (flattened state) of gold, the peak of the absorption, scattering and extinction spectra increases, which can be a good option for plasmonic applications and optical devices. Also, compared to ellipsoidal nanoparticles (elongated state), the absorption and extinction efficiencies intensity are higher and the scattering peak appears at higher wavelengths, while for the elongated state, ellipsoidal nanoparticles do not show such a case. Due to the small number of conducting electrons in nanoparticles and the homogeneous displacement of free charges within the nanoparticle, it is only the bipolar distribution of free charges that causes single peaks in the extinction and absorption spectrum of ellipsoidal gold and silver nanoparticles.