Superlenses earned their superlative by being able to capture the
“evanescent” light waves that blossom close to an illuminated surface
and never travel far enough to be “seen” by a conventional lens.
Superlenses hold enormous potential in a range of applications,
depending upon the form of light they capture, but their use has been
limited because most have been made from elaborate artificial constructs
known as metamaterials. The unique optical properties of metamaterials,
which include the ability to bend light backwards – a property known as
negative refraction – arise from their structure rather than their
chemical composition. However, metamaterials can be difficult to
fabricate and tend to absorb a relatively high percentage of photons
that would otherwise be available for imaging.