Enhancement of nonlinear susceptibilities near plasmonic metamaterials

It is shown that the Kerr nonlinearity of a two-level atom placed in the vicinity of a two-dimensional array of metal-coated silica nanoparticles can be greatly enhanced due to quenching of both radiative and non-radiative spontaneous-emission paths for frequencies near the surface plasmon resonances. The spontaneous emission rate is calculated by rigorous electrodynamic calculations of the electric-field Green’s tensor. The Kerr susceptibility can be enhanced by two orders of magnitude even for large detunings heralding, this way, the observation of nonlinear phenomena for moderate radiation intensities.