Removing singular refractive indices with sculpted surfaces.
The advent of Transformation Optics established the link between geometry and material properties, and has resulted in a degree of control over electromagnetic fields that was previously impossible. For waves confined to a surface it is known that there is a simpler, but related, geometrical equivalence between the surface shape and the refractive index, and here we demonstrate that conventional devices possessing a singularity - that is, the requirement of an infinite refractive index - can be realised for waves confined to an appropriately sculpted surface. In particular, we redesign three singular omnidirectional devices: the Eaton lens, the generalized Maxwell Fish-Eye, and the invisible sphere. Our designs perfectly reproduce the behaviour of these singular devices, and can be achieved with simple isotropic media of low refractive index contrast.
Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, United Kingdom.
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Horsley
Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, United Kingdom.
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Hooper
School of Electronic Engineering and Computer Science, Queen Mary University of London, London E1 4NS, United Kingdom.
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Mitchell-Thomas
School of Electrical Engineering, KTH Royal Institute of Technology, SE-10044, Stockholm, Sweden.
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Quevedo-Teruel