Negative refractive perfect lens vs Spherical geodesic lens. Perfect   Imaging comparative analysis
  Negative Refractive Lens (NRL) has shown that an optical system can produce images with details below the classic Abbe diffraction limit. This optical system transmits the electric field, emitted by the object surface, towards the image surface producing the same field distribution in both surfaces. In particular, a Dirac delta electric field in the object surface is focused without diffraction limit to the Dirac delta electric field in the image surface. The Maxwell Fish Eye lens (MFE) and the Spherical Geodesic Waveguide (SGW) have been claimed to break the diffraction limit using positive refraction with a different meaning. In these cases, it has been considered the power transmission from a point source to a point receptor, which falls drastically when the receptor is displaced from the focus by a distance much smaller than the wavelength. Although these systems can detect displacements up to Wavelength/500, they cannot be compared to the NRL, since the concept of the object and image surface is not established. Here, it is presented an analysis of the SGW with defined object and image surfaces. The results show that a Dirac delta electric field on the object surface produces an image below the refraction limits on the image surface. 
Juan C. Gonzalez, Pablo Benitez, Juan C. Minano and Dejan Grabovickic
physics.optics