" With the advent of nanotechnology, microfabrication has produced novel manmade constructs called metamaterials which exhibit entirely new properties in terms of their effect on light, effects which are not found in conventional materials, or even in nature itself. Early in the 21st century, a chance observation showed that an ultrathin layer of silver on a flat sheet of glass would act like a lens, and from this point, the development of the ‘perfect’ or ‘superlens’ began, with the theoretical possibility to image details such as viruses in living cells with a light microscope, bypassing Abbe’s diffraction limit. Metamaterials have been produced that make this possible, as they have a property previously unimagined in optics, and not found in nature, which is a negative refractive index. "

― , Microscopy: A Very Short Introduction