Broadband Four‐Wave Mixing Enhanced by Plasmonic Surface Lattice Resonance and Localized Surface Plasmon Resonance in an Azimuthally Chirped Grating

Plasmonic enhancement of nonlinear light–matter interaction can be achieved via dedicated optimization resonant plasmonic modes that are spectrally matched to the different wavelengths involved in particular optical process. Here, generation and broadband four-wave mixing (FWM) investigated a azimuthally chirped grating (ACG). The varying periodicity an ACG offers well-defined channel mediate near field far over broad range wavelengths. However, mechanism responsible for such platform depends on interplay between effects manifested by both groove geometry grating's periodicity. This work delineates collective contribution geometry-dependent localized surface plasmon resonance periodicity-dependent lattice bring into effect FWM ACG.