1202.4413 (Satvik N. Wani et al.)

Effective permittivity of random plasmonic composites    [PDF]

Satvik N. Wani, Ashok S. Sangani, Radhakrishna Sureshkumar

An effective-medium theory (EMT) is developed to predict the effective
permittivity \epsilon_eff of dense random dispersions of high
optical-conductivity metals such as Ag, Au and Cu. Dependence of \epsilon_eff
on the volume fraction \phi, a microstructure parameter \kappa related to the
static structure factor and particle radius a is studied. In the electrostatic
limit, the upper and lower bounds of \kappa correspond to Maxwell-Garnett and
Bruggeman EMTs respectively. Finite size effects are significant when
|\beta^2(ka/n)^3| becomes O(1) where \beta, k, and n denote the nanoparticle
polarizability, wavenumber and matrix refractive index respectively. The
coupling between the particle and effective medium results in a red-shift in
the resonance peak, a non-linear dependence of \epsilon_eff on \phi, and Fano
resonance in \epsilon_eff.

View original: http://arxiv.org/abs/1202.4413