Second harmonic generation in plasmonic Nanoresonators

We study second harmonic generation from dipole gold nanoantennas by analyzing the different contributions of bulk and surface nonlinear terms. Numerical calculations have been performed applying a Green's tensor method. The SHG as a function of the wires cross section size is investigated in both the near and far field regimes. We show that the excitation of localized surface plasmon polaritons in these structures can remarkably modify the nonlinear response of the system by enhancing surface and/or bulk contributions, creating regimes where bulk nonlinear terms dominate over surface linear terms and vice versa. We also report results of calculations performed on Silver coupled 2D-nanoresonators. Coupling is responsible for the formation of resonant modes that can be localized on small portions of the structure or distributed over the whole structure.