Infrared surface waves on semiconductor and conducting polymer

摘要

Conductors with infrared plasma frequencies are potentially useful hosts of surface electromagnetic waves with sub-wavelength mode confinement for sensing applications. Such materials include semimetals, semiconductors, and conducting polymers. In this paper we present experimental and theoretical investigations of surface waves on doped silicon and the conducting polymer polyaniline (PANI). Resonant absorption features were measured in reflection from lamellar gratings made from doped silicon for various p-polarized CO2 laser wavelengths. The angular reflectance spectra for doped silicon was calculated and compared with the experiments using experimental complex permittivities determined from infrared (IR) ellipsometry data. Polyaniline films were prepared, optical constants determined, and resonance spectra calculated also. A specific goal is to identify a conductor having tight mode confinement, sharp reflectivity resonances, and capability to be functionalized for biosensor applications.