Growth and characterization of large-scale Ti: sapphire crystal using heat exchange method for ultra-fast ultra-high-power lasers

Large-scale titanium-doped sapphire (Ti:sapphire) crystal was grown in a 380 mm diameter molybdenum crucible using the heat exchange method (HEM) and characterized. The diameter of the core Ti: sapphire single crystal was estimated to be slightly larger than 200 mm. A Ti:sapphire crystal wafer 157 mm in diameter and 28 mm thick was obtained. Characterization based on X-ray diffraction spectroscopy, Raman spectroscopy, and absorption and fluorescence spectroscopy was carried out. The as-grown Ti:sapphire crystal had high intrinsic quality and a large figure of merit (FOM) without additional annealing. The high optical quality of the as-grown Ti:sapphire crystal indicated it is suitable for ultra-fast ultra-high-power lasers in chirped pulse amplification systems.