|Illustration of negative refraction taken from On The Properties of
Report Author: W.O.L. Bellamy, M.T.A. Hatcher et al.
Optical metamaterials are an artificial type of composite material, with the unique property of refracting light ‘negatively’, or in the opposite way to conventional materials using the conventional optical model. Due to this they are also known as Negative Index Materials (NIMs) or Left-Handed Materials (LHMs). The field of optical metamaterials was originally conceived by Soviet scientist Victor Veselago in 1967 with the theoretical possibility of negative refraction using a combination of both simultaneously negative permeability and permittivity values. It was not until Sir John Pendry’s further theoretical work on this concept enabled the first physical demonstration of negative refraction by Dr D.R. Smith in 2001. Pendry showed that it was possible to create an effective negative permittivity and permeability on a scale larger than the atomic scale, using artificial composite structures in a repeating pattern, so it is possible to produce negative refraction. This is the principle which has since enabled the development of optical metamaterials. One of the theoretical uses and practical goals of developing these materials is the construction of ‘superlenses’ that would have far superior focusing precision compared to conventional lenses. Another exciting possibility is the development of cloaking devices which could have the property of making an object appear ‘invisible’ – this is a use that is not only limited to the optical scale but can be utilised at other frequencies of the electromagnetic spectrum. Currently, there are rapid advances being made in this field, and the next few years should see the unlocking of their full potential.