Giant optical transmission of subwavelength apertures for NSOM and data storage

The optical transmission through a single, sub-wavelength aperture in a metal film is strongly enhanced when the incident light is resonant with a surface plasmon mode at the metal surface. The interaction is allowed when the surface surrounding the aperture has periodic corrugations. We discuss the physics of the transmission enhancement, and optimize the geometry of the corrugation to yield the maximum enhancement. We discuss the implications of this effect on high-density data storage and NSOM applications.