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

TL;DR

This paper explores how azimuthally chirped plasmonic gratings enhance broadband four-wave mixing through combined localized surface plasmon resonance and surface lattice resonance effects.

Contribution

It demonstrates the collective role of groove geometry and periodicity in enhancing broadband FWM in a novel azimuthally chirped grating platform.

Findings

Enhanced broadband FWM observed in azimuthally chirped gratings.

Both LSPR and PSLR contribute to field enhancement.

Broad spectral range of nonlinear interaction achieved.

Abstract

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