Divergent nonlinear optical response of three resonator system via Fano resonances

In a previous study, we have discovered that nonlinear processes can be enhanced several orders of magnitude due to the path interference effects which are introduced by Fano resonances. Emergence of this phenomenon has been demonstrated also in 3-dimensional solutions of Maxwell equations. However, enhancement has been found to be limited by the decay rate of the plasmonic oscillations. In the present work, we demonstrate that such a limitation can be lifted o? when the path interference from two quantum emitters to a plasmonic resonator (second harmonic converter) is considered. Enhancement factors much larger than 7 orders of magnitude are possible using such an interference scheme. Therefore, a single hybridized system of 3 particles (manufactured carefully) can account for almost all of the second harmonic generated radiation emitted from a sample of plasmonic particle clusters decorated with quantum emitters (e.g. a spaser).