  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.
