Thermal and Optical Characterization of Undoped and Neodymium-Doped Y3ScAl4O12 Ceramics

Y3–3xNd3xSc1Al4O12 (x = 0, 0.01, and 0.02) ceramics were fabricated by sintering at high temperature under vacuum. Unit cell parameter refinement and chemical analysis have been performed. The morphological characterization shows micrograins with no visible defects. The thermal analysis of these ceramics is presented, by measuring the specific heat in the temperature range from 300 to 500 K. Their values at room temperature are in the range 0.81–0.90 J g1–K–1. The thermal conductivity has been determined by two methods: by the experimental measurement of the thermal diffusivity by the photopyroelectric method, and by spectroscopy, evaluating the thermal load. The thermal conductivities are in the range 9.7–6.5 W K–1 m–1 in the temperature interval from 300 to 500 K. The thermooptic coefficients were measured at 632 nm by the dark mode method using a prism coupler, and the obtained values are in the range 12.8–13.3 × 10–6 K–1. The nonlinear refractive index values at 795 nm have been evaluated to calibrate the nonlinear optical response of these materials.This work is supported by the Spanish Government under projects MAT2011-29255-C02-01-02, MAT2013-47395-C4-4-R, and the Catalan Government under project 2014SGR1358. It was also funded by the European Commission under the Seventh Framework Programme, project Cleanspace, FP7-SPACE-2010-1-GA No. 263044

Thermo optical coefficient of tin-oxide films measured by ellipsometry

International audienc

Glass-ceramics coating of silica microspheres

Sub-conference: 3rd Workshop of European Action COST MP0702 « Towards Functional Sub-Wavelength Photonic Structures », Topic: Plasmonics, Metamaterials, and Non-reciprocity, session Fr2B « COST WG1 » [Fr2B.2 ] http://www.univ-angers.fr/icton/International audienceSilica spheres with diameters in the order of 100 µm were coated by Er3+-activated silica-hafnia films and then annealed in order to induce formation and growth of nanocrystals. The spectroscopic and morphologic properties of the spheres have been characterized by photoluminescence and atomic force microscopy techniques, respectively. The preliminary information are discussed, taken in account the previous consolidated results obtained in the case of amorphous and glass-ceramic waveguides as well as spherical microresonators coated by amorphous silica-hafnia films