Random porous silicon dielectric multilayers are proposed as interesting materials for applications as optical components. Distributed Bragg reflectors and interferential Fabry-P érot filters are demonstrated. The randomness is obtained as a variation in the layer thicknesses. The advantage in the use of random instead of periodic multilayers lies in the obtention of a wider stop-band in Bragg reflectors with the same difference in the refractive indexes of the layers and in a higher finesse in Fabry-P érot filters.

Textured alumina ceramics were obtained by Spark Plasma Sintering of undoped commercial a-Al 2 O 3 powders. Various parameters (density, grain growth, grain size distribution) of the alumina ceramics, sintered at two typical temperatures 1400 C and 1700 C, are investigated. Quantitative textural and structural analysis, carried out using a combination of Electron Back Scattering Diffraction and X-ray diffraction, are represented in the form of mapping and pole figures. The mechanical properties of these textured alumina ceramics include high elastic modulus and hardness values with high anisotropic nature, opening the door for a large range of applications. V C 2013 AIP Publishing LLC [http://dx

No abstract