Intense Focusing Of Light Using Metals

J.B. Pendry

 

We are familiar with the fact that in vacuo light may only be focused to an area of the same order as the wavelength. However metal surfaces support plasma modes that couple to incident light, and the focusing of surface plasma modes is not restricted by the free space wavelength. Such nanofocusing offers the possibility of huge concentrations of radiative energy in very small volumes, impossible to achieve with conventional focusing with lenses. For very modest power input, local concentrations of energy may be great enough to excite nonlinear effects that depend on the intensity.