Discrete light spectrum of complex-shaped meta-atoms

We investigate the potentials of open plasmonic resonators (meta-atoms) with different shapes in the context of light trapping. Consistent with the theory of Silveirinha (2014), it is found that in some conditions complex-shaped dielectric cavities may support discrete light states screened by volume plasmons that in the limit of vanishing material loss have an infinite lifetime. The embedded eigenstates can be efficiently pumped with a plane wave excitation when the meta-atom core has a nonlinear response, such that the trapped light energy is precisely quantized.