Acceleration of photochemical hole burning rate for Sm 2+-doped borate glasses by X-ray irradiation

Abstract

The mechanism of persistent spectral hole burning (PSHB) for Sm 2+-doped solids is known to be the photoionization of Sm 2+ ions, but the detailed processes of hole burning and hole burning kinetics are not clear at this moment. We have investigated the effect of X-ray irradiation on photochemical hole burning and structural changes of Sm 2+-doped borate glasses. The X-ray irradiation and hole burning measurements were performed at room temperature. As a result, the hole depth and width increased after X-ray exposure, and the hole burning rate was increased for all X-ray irradiated specimens. Local structure around the rare earth ions such as symmetry or the number of non-bridging oxygens was changed by X-ray irradiation. These experimental results were explained by the radiation damaged structure of glasses.