Thèse de doctorat en Physique
Sous la direction de Thomas W. Ebbesen.
Soutenue en 2004
à Strasbourg 1 .
On the back side of the mirror : Study of the enhanced transmission of light through subwavelength apertures in metal films
The work described in this thesis covers diverse aspects of the optical transmission through subwavelength apertures. It was motivated by the discovery of the extraordinary transmission through subwavelength apertures in metal film where the enhancement is due to the coupling of light to surface plasmons. We showed that the extraordinary transmission in the sub-wavelength regime is a tunnelling phenomenon enhanced by surface plasmons, as predicted by theoretical investigations, and that the transmission is very sensitive to the dielectric constant of the metal. By studying a single aperture surrounded by periodic corrugations, we noticed that the shape of the wavefront can be tailored by a periodic milling of the output surface. In such a way, the beam with a small angular divergence can be created thereby surmounting the standard diffraction of small apertures. Furthermore it is shown that the transmission process can be separated into three separate independent steps: coupling in, transmission through the aperture and coupling out. Finally, we discovered that even isolated subwavelength apertures give rise to transmission peaks at certain wavelengths. This is due to the activation of localized surface plasmons on the rim of the aperture. This result challenges the understanding and theoretical description of the transmission of single holes.