A graphene-inspired electromagnetic superlens
Silveirinha, M. G.
A graphene-inspired electromagnetic superlens, Proc EIEC - XII Iberian Meeting on Computational Electromagnetics, Coimbra, Portugal, Vol. , pp. - , May, 2018.
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The ability to transport both propagative and evanescent parts of electromagnetic waves is the key ingredient to create perfect imaging devices with a resolution not limited by the diffraction of light. In that respect, the groundbreaking discovery that a slab of material with index of refraction equal to minus one, the so-called superlens, is able to focus not only the far-field but also the near-field components of electromagnetic radiation generated a strong excitement in the scientific community. In particular motivated by this idea, electronic counterparts of the electromagnetic superlens were later proposed in graphene superlattices or in semiconductor superlattices. Here, we adopt the opposite perspective and design a photonic superlens based on its electronic counterpart. First, inspired by previous results, we show that a simple interface between two graphene sheets with different orientations may enable negative refraction for electrons and a perfect electronic tunneling for all incident angles. Then, by using a strict analogy between the two dimensional Schrödinger and Maxwell equations, we transpose this scheme to photonic crystals with honeycomb symmetry made of dielectric cylinders embedded in a metallic background, and demonstrate with full-wave simulations perfect focus and negative refraction in a lens made of such a structure. Because of the non-resonant character of this system, losses are not too important and it is expected that such lenses may have a strong potential for practical applications.