Resonances on-demand for plasmonic nano-particles.

A method for designing plasmonic particles with desired resonance spectra by exploiting the interaction of local geometry with surface charge distribution and applying evolutionary algorithm is presented. The method is based on repetitive perturbations of an initial particle's shape while calculating the eigenvalues of the various quasistatic resonances. Novel family of particles with collocated dipole-quadrupole resonances was designed, as an example for the unique power of the method.