Tiny apertures with a big future

Abstract

Sub-wavelength apertures once seemed like boring entities to physicists because they were thought to transmit only a very small amount of light. Moreover, the transmitted light emerged from the aperture uniformly in all directions. This so-called diffraction limit has placed a fundamental restriction on the scale with which light can be manipulated, and has therefore limited the development of certain micro-photonics technologies. In recent years, however, things have changed, and the optical properties of sub-wavelength apertures have become one of the most exciting areas of optics research.