Estimation of Field depolarization and LSPR shift in closely packed metallic Nanoparticles with corrected plasmon line width

Abstract

Using modified Yamaguchi model (MYM) along with wavelength dependent plasmon line-width correction, we have developed an analytical model which can calculate effective optical constants of any distribution of ellipsoidal nanoparticles using their morphological parameters. Present approach has been developed using exact expression of electric field outside an ellipsoid and thus the shape dependent interaction of nanoparticle for higher filling fraction has been calculated exactly. Limitations of widely used point dipole approximations and effective medium theories have been discussed and compared with present approach. Previously reported shape dependent expression for plasmon line-width has been incorporated to calculate effective optical constants of the array of nanoparticles system for in-plane and out of plane plasmons. Effect of interparticle distance has been discussed with the direction of polarization for various shapes of nanoparticles. Special case of ripple patterned supported elongated nanoparticles has been discussed and biaxial anisotropic behavior in optical constants of such structures has been understood analytically for the first time. © 2017 Elsevier B.V.