On percolation and circular Bragg phenomenon in metallic, helicoidally periodic, sculptured thin films

Abstract

The concept of local homogenization is invoked in the visible and the sub-visible frequency regimes to estimate the permittivity dyadics of a thin-film helicoidal bianisotropic mediums (TFHBMs) -a canonical class of sculptured thin films with helicoidally periodic microstructuremade of a metal. Examination of the components of the permittivity dyadics, as well as of the co-and the cross-polarized reflectances of axially excited, metallic TFHBM halfspaces, reveals that three different absorbing-dielectric-to-metal transitions will occur as the metallic volumetric fraction is increased, but only two will be optically sensed using normally incident plane waves. The first transition is show to virtually eliminate the circular Bragg phenomenon characteristically displayed by axially excited, dielectric TFHBMs.

Influence of Oblique Angle Deposition on the Nano-structure and Characteristics of ZnO Thin Films Produced by Annealing of Zn Films

“…The ellipsoids are considered to be electrically small (i.e., small in a sense that their electrical interaction can be ignored). [45][46][47] The three diameters of the ellipsoids are dimensionless and of arbitrary sizes. In general, one of the diameters is considered as unity (e.g., 1 nm) and the other two are valued relative to this diameter.…”

Characteristics of Plasmonic at a Metal/Chiral Sculptured Thin Film Interface

“… of CSTF were calculated using the Bruggeman homogenization formalism [19], as it is shown in Fig.2. In this formalism, the structure is considered as a two component composite (MgF 2 and void).…”

Post- versus pre-resonance characteristics of axially excited chiral sculptured thin films

“…Indeed, light of one circular polarization -coincident with the structural handedness of the chiral STF -effectively encounters a grating in the Bragg regime, while light of the opposite circular polarization state does not [3,4]. The described phenomenon has been theoretically established for chiral STF half-spaces as well [5,6].…”

“…These coefficients are doubly subscripted: those with both subscripts identical refer to copolarized, while those with two different subscripts denote cross-polarized, reflection. These coefficients can be calculated by following the procedure recorded elsewhere [5,6]. for chiral liquid crystals too [12].…”