META Conference, META'12

Font Size: 
General description of surface waves excited on metallic gratings with subwavelength patterns
Haitao Liu, Philippe Lalanne

Last modified: 2011-12-15

Abstract


Under illumination by a transverse-magnetic (TM) wave, the electromagnetic field scattered on metallic surfaces corrugated by one-dimensional periodic arrays of tiny indentations exhibits several general properties. In general, the field on the surface between the indentations does not contain any surface plasmon polariton (SPP). Exception occurs in a narrow energy band centered around l=lSP, the SPP-phased matched wavelength obtained when the momentum of the incident wave matches the SPP momentum of the flat interface. When l=lSP, the field on the surface is always purely plasmonic even at infrared frequencies, for which SPP are excited nonresonantly. These properties are derived under the sole assumption that the indentations are small compared to the wavelength and are independent of the indentations form or dielectric constant, of the incident field and of the existence of an eventual resonance or antiresonance. A simple and general formula describing the fraction of the surface field that is composed of SPP is also obtained.

Keywords


plasmonics; surface plasmon polariton; metallic gratings; general properties