Giant optical transmission of sub-wavelength apertures: physics and applications

The transmission of light through an aperture in a metal film is extremely small when the aperture diameter is much smaller than the optical wavelength. But when the metal surface surrounding the subwavelength hole is corrugated, the incident light can couple to surface plasmons (SP), excitation modes on the metal surface. A resonant interaction leads to an enhanced transmission at wavelengths determined by the corrugation pitch. We discuss applications of the SP enhanced transmission in near-field scanning optical microscopy and in high-density optical data storage. (Author)