Optical studies in gamma irradiated Mg doped CaF2 single crystals

Pure and Mg doped CaF2 single crystals grown by the Bridgman method were irradiated with gamma rays (gamma-rays) for doses ranging from 97 Gy to 9.72 KGy. The pristine samples showed minimal absorption indicating the purity of the samples. The gamma-irradiated pure CaF2 crystals showed prominent and strong absorption with a peak at similar to 374 nm besides three weak ones at similar to 456, 523 and 623 nm. However gamma-rayed Mg doped crystals showed a prominent absorption with a strong peak at similar to 370 nm and a broad one at similar to 530 nm. The absorption indicated the generation of F and F-aggregate centers in the irradiated crystals. The photoluminescence (PL) emission spectrum of both pure and Mg doped crystals showed prominent emission at similar to 390 nm when they were excited at similar to 250 nm. Also, when the samples were excited at 323 and 363 nm strong emissions were observed at similar to 430 and 422 nm respectively. The optical absorption and PL intensities were found to increase with increase in dose. (C) 2010 Elsevier B.V. All rights reserved