Polaritonic and photonic gaps in SiO2/Si and SiO2/air periodic structures

Abstract The one-dimensional (1D) photonic crystals (PhC) Si/SiO 2 , SiO 2 /Si and SiO 2 /air are studied to investigate the coexistence and interaction of polaritonic and structural gaps. Optical multilayer calculations as well as infrared reflectance measurements in the 2.7–12 μm range for relevant cases have been carried out. The samples were prepared by standard chemical vapor deposition (CVD) processes. Satisfactory agreement between experimental and calculated results was obtained without fitting. The calculated results verify the presence of a polaritonic gap for thicknesses much lower than the wavelength for the cases SiO 2 /Si and SiO 2 /air. Including also the case Si/SiO 2 , we find the polaritonic peak can be strengthened, unchanged, or extinguished by the interaction between structural and polaritonic effects. All these predictions have been experimentally verified.