Iranian Journal of Materials Science and Engineering

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High quality GGG:Cr,Ca crystal for passive Q-switching Nd:garnet lasers has been grown by the Czochralski method. Thermal treatment of GGG crystals co-doped with Cr4+ and Ca2+ at different temperatures is investigated. The absorption spectra were resolved into different peaks, of modified Gaussian line-shape. Transition from octahedral sites to tetrahedral ones is thermally activated. An optimal temperature interval for this transition was found to be 1200-1300 ˚C. The investigated samples were used as saturable absorbers in flash-lamp pumped Nd:YAG laser, and a pulse width of about 16 nsec was obtained