Abdeldjelil Nehari

Enabling cryogenic Gravitational Waves detectors: growth of sapphire crystals with record low absorption in the near infrared Sapphire were grown along the C-axis using Czochralski method to achieve the ultra-low absorption of 11 ppm/cm. We point toward the crucial role of Fe2+- Fe3+ and Ti3+- Ti3+ pairs in the absorption at 1064nm. The results open the route to upscaling the conditions to achieve large crystals for the next generation of gravitational wave detector.

Cr-doped Al2O3-YAG binary and Al2O3-YAG-ZrO2 ternary eutectic materials crystallized by the micro pulling down technique and their characterization Kheirreddine Lebbou, Jie Xu, Yannick Guyot, Abdeldjelil Nehari, Anne Pillonnet, Hiroaki Takeda, Xiaodong Xu and Gilles Ledoux Abstract Cr -doped Al2O3-YAG and Al2O3-YAG-ZrO2 eutectic ceramics rods of 3mm in diameter were solidified from the melt by micro-pulling down (µ-PD) technique.