Authors:Andrew J. Mackay
Source:FERMAT, Articles, 2016-Vol15-May_Jun-001
Abstract:There is considerable interest in sub-wavelength imaging using metamaterials, for example using double negative isotropic materials or hyperbolic anisotropic materials. It is shown here that sub-wavelength imaging is possible using more conventional bulk isotropic materials with positive relative permeability r and relative permittivity µr greater than unity. There are practical advantages to this approach. Firstly, such materials are inherently non-dispersive so that large bandwidths may be obtained. Secondly, conventional dielectric materials are available with low loss from radio to optical frequencies. Thirdly, difficult fabrication processes may be avoided. This letter provides examples using a magneto-electric material with r = µr in order to reduce interface reflections due to impedance mismatch while establishing proof of principal. The method uses a lens designed to ensure that rays in the medium, generated by evanescent modes near the source, are converted into free space propagating waves.
Index Terms:metamaterials, super-resolution, superlens, imaging, ray tracing, evanescent waves
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Sub-wavelength imaging without metamaterials