Optic axis-driven new horizons for hyperbolic metamaterials
Joule Physics Laboratory, Materials & Physics Research Centre, University of Salford, Greater Manchester
M5 4WT, UK
2 Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2AZ, UK
* e-mail: email@example.com
Accepted: 28 October 2015
Published online: 26 January 2016
The broad assertion here is that the current hyperbolic metamaterial world is only partially served by investigations that incorporate only some limited version of anisotropy. Even modest deviations of the optic axis from the main propagation axis lead to new phase shifts, which not only compete with those created by absorption but end up dominating them. Some progress has been attempted in the literature by introducing the terms “asymmetric hyperbolic media”, but it appears that this kind of asymmetry only involves an optic axis at an angle to the interface of a uniaxial crystal. From a device point of view, many new prospects should appear and the outcomes of the investigations presented here yield a new general theory. It is emphasised that the orientation of the optic axis is a significant determinant in the resulting optical properties. Whereas for conventional anisotropic waveguides homogeneous propagating waves occur over a limited range of angular dispositions of the optic axis it is shown that for a hyperbolic guide a critical angular setting exists, above which the guided waves are always homogeneous. This has significant implications for metawaveguide designs. The resulting structures are more tolerant to optic axis misalignment.
Key words: Metamaterial / Hyperbolic / Uniaxial / Optic axis
© A.D. Boardman et al., published by EDP Sciences, 2016
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