Tailoring of electromagnetic field localizations by two-dimensional graphene nanostructures

Abstract

Graphene has great potential for enhancing light−matter interactions in a two-dimensional regime due to surface plasmons with low loss and strong light confinement. Further utilization of graphene in nanophotonics relies on the precise control of light localization properties. Here, we demonstrate the tailoring of electromagnetic field localizations in the mid-infrared region by precisely shaping the graphene into nanostructures with different geometries. We generalize the phenomenological cavity model and employ nanoimaging techniques to quantitatively calculate and experimentally visualize the two-dimensional electromagnetic field distributions within the nanostructures, which indicate that the electromagnetic field can be shaped into specific patterns depending on the shapes and sizes of the nanostructures. Furthermore, we show that the light localization performance can be further improved by reducing the sizes of the nanostructures, where a lateral confinement of λ0/180 of the incidence light can be achieved. The electromagnetic field localizations within a nanostructure with a specific geometry can also be modulated by chemical doping. Our strategies can, in principle, be generalized to other two-dimensional materials, therefore providing new degrees of freedom for designing nanophotonic components capable of tailoring two-dimensional light confinement over a broad wavelength range.

Emergent scale invariance of nonclassical plasmons in graphene nanoribbons

“…By combining Eqs. (18) and (19) we can find the plasma energies as a function of the ribbon width. For our purposes it is essential to realize that Eq.…”

Resonant nanostructures for highly confined and ultra-sensitive surface phonon-polaritons

“…This is represented by the appearance of an additional maximum in the field distribution inside the resonator. The experimental results are supported by simulations carried out using the phenomenological model 52,53 , which accounts for all possible reflections of a tip-launched wave in the resonator travelling with the measured polariton wavelength (see "Methods" section for more details). The simulated field distributions are plotted in Fig.…”

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