Refractive index, dispersion, and birefringence of silicon carbide polytypes.
The refractive index of each of the four common silicon carbide polytypes has been measured over the visible range. The data were analyzed in an attempt to relate the birefringence to the relative hexagonal character of the polytype. A general relationship exists, namely, that the birefringence increases with increasing hexagonal character of the polytype. This relationship is not sufficiently precise to use for the identification of polytypes.
Three-dimensional nanotransmission lines at optical frequencies: A recipe for broadband negative-refraction optical metamaterials
We apply the optical nanocircuit concepts to design and analyze in detail a three-dimensional (3D) plasmonic nanotransmission line network that may act as a relatively broadband negative-refraction metamaterial at infrared and optical frequencies. After discussing the heuristic concepts in our theory, we show full-wave analytical results of the expected behavior of such materials, which show increased bandwidth and relative robustness to losses. The possibility and constraints of getting a 3D fully isotropic response are also explored and conditions for minimal losses and increased bandwidth are discussed. Full-wave analytical results for some design examples employing realistic plasmonic materials at infrared and optical frequencies are also presented, and the case of a subwavelength imaging system using a slab of this material is numerically investigated.
Eindimensionale Fehlordnung in Kristallen und ihr Einfluss auf die Röntgeninterferenzen. III. Vergleich der Berechnungen mit experimentellen Ergebnissen
Some experimental results are here compared with calculations previously communicated. Wurtzite crystals from Thrace show a high degree of disorder which cannot have arisen from transformation of parts of the crystal into zincblende. The rhombohedral modification of carbon seems to be the more stable one at low temperatures. Rotation photographs of SiC (II) crystals show a low degree of disorder and the general course of the diffuse scattering resembles that of a slightly disordered crystal of the SiC (III) type.