Near-field and Far-field Optical Properties of Silver Nanospheres: Theoretical and Experimental Investigations of the Size, Shape, Dielectric Environment, and Composition Effects

Collective oscillation of electrons in the conduction band of noble metal nanoparticles is known as localized surface plasmon resonance (LSPR) phenomena. Investigations of the LSPR include non-radiative near-field behavior near metal nanoparticles and radiative far-field behavior at greater distances which depend on geometric and structural properties of nanoparticles. So, these behavior of the LSPRs can easily be tuned by changing these properties for different applications in biosensors, communications, and optics. In this paper, we investigated the effects of the size, shape, dielectric environment, and composition on near-field and far-field optical properties of silver nanospheres, theoretically and experimentally. For this purpose, silver nanospheres with different diameter sizes, silver nanowires, silver nanocubes, and gold nanospheres were synthesized and characterized and also the two-dimensional finite-difference time-domain (FDTD) method was used for simulations. The results show that the theoretical and experimental studies are in good agreement.