Shaun Williams

The Infrared Enhanced Transmission of Metallic Subwavelength Arrays: Characteristics and Applications Shaun Williams

Nickel mesh with holes spaced by 12.7 microns show a higher fractional transmission than the fractional open area of the mesh. This effect is attributed to surface plasmons which allow light incident on one side of the metal mesh to be transmitted to the other side where it is released as light. Due to the hole spacing of this mesh, the surface plasmon phenomenon is seen in the infrared. Coating the nickel mesh with other metals allows the effect of the metal and the hole size on transmission. The increased transmission has been used to study molecular species which are bound to the surface of the mesh. The reaction that converts methanol to formaldehyde has been studied. Due to the unique spectroscopic properties of the mesh, surface species exhibit increased spectroscopic aborptions. The absorptions are enhanced to such an extent that the reactants, products and the adsorbed methoxy radical intermediate have been observed with significant intensity. The techniques will be useful for chemists and physicists alike.