Mechano-Optical Resonant Emission by Edge Angle Modulation of Wrinkled Graphene on Plasmonic Metal Gratings

Graphene coated on top of photonic-plasmonic metasurfaces can produce resonant radiative emission in the midinfrared region. Narrowband emission peaks are observed through folding graphene into "origami" ridges over metal grating grooves, creating a complementary cavity mode above the trench. This geometrically tuned phenomenon of graphene surface plasmon excitation along the folded sheet enhances the emission when added to magnetic polariton (MP) resonance induced within the plasmonic grating groove. Our analytical models describe how this graphene surface plasmon polariton (SPPG) is a function of folded graphene geometric parameters, and most importantly, the graphene edge angle that distends from the grating surface. The frequency-dependent phase shift of SPPG is fitted to grating parameters, and a modified inductor-capacitor circuit model was developed for predicting MP resonance mode with graphene influence. It was found that the edge angle of wrinkled graphene blue-shifts the groove MP resonance and SPPG resonant emission peak in both wrinkled graphene alone and with the grating substrate. The understanding of geometrically modulated graphene adhered on plasmonic gratings impacts the design and capability of narrowband cavity emitters and contributes toward the development of mechanical-optical environmental sensors.