Effects of annealing treatment and gamma irradiation on the absorption and fluorescence spectra of Cr:GSGG laser crystal

摘要

The influence of annealing treatments and gamma-ray irradiation on the absorption and fluorescence spectra of CnGSGG crystals grown by the Czochralski method has been investigated. Two absorption bands located near 686 nm and 1050 nm were weakened markedly after the crystal was re-annealed in H_2 atmosphere, which is due to the Cr~(4+) ions being de-oxidized into Cr~(3+) ions. The other two weak additional absorption bands induced by gamma-ray irradiation appearing near 310 nm and 480 nm are ascribed to the Fe~(2+) ions and F-type color centers, respectively. In particular, the gamma-ray irradiation with a dose of 100 Mrad has an effect of improving slightly the luminescence properties of CnGSGG crystals. The improvement mechanism is analyzed and discussed.