Numerical simulation of optical properties for silver nanoparticles of different shapes in vacuum and water

The paper presents the results of using the finite-difference time-domain (FDTD) method to simulate the optical properties of silver nanoparticles (AgNPs) of different shapes. The calculations were carried out in a medium with the refractive index of water (H₂O) and in vacuum, under the incidence of polychromatic radiation. The distributions of the maximum electric field strength as a function of incident radiation wavelength were calculated and plotted. The optical parameters, such as absorption, scattering, and extinction cross sections, were calculated using Ansys Lumerical FDTD software. A complex theoretical explanation of the obtained optical properties in terms of nanoplasmonics is provided. In particular, the patterns of resonant optical peak distribution as a function of irradiation wavelength are discussed. Furthermore, the paper demonstrates the potential tuning of nanoobjects optical properties with various geometries, obtained through controlled synthesis for various fields of applied nanoplasmonics in the H₂O medium. Since colloidal nanoparticles are produced using physical and chemical methods in aqueous solutions, the obtained results can be useful and important for the nanoparticles controlled synthesis and saving laboratory resources.