In collaboration with a team of scientists at Duke University, John has developed the concept of ‘transformation optics’, or TO for short, which prescribes how electromagnetic lines of force can be manipulated at will. His latest research applies TO to the study of surface plasmons. The surfaces of metals such as gold and silver support density oscillations of the electrons, much like waves on a sea. These can couple to external radiation, but have a much shorter wavelength. The plasmonic excitations are greatly influenced by the shape of the surface and in particular by any singularities such as sharp corners, touching surfaces, or other rough features, which tend to attract very high field intensities: they act as harvesting points for any incident radiation.
Metamaterials, Transformation optics, Plasmonics