Photochemical hole burning and local structural change in Sm2+-doped borate glasses

Photochemical hole burning (PHB) not only can be applied for data storage systems but also serves as a powerful method for studying the local structure around optical centers. The present work investigated the effects of aluminum, magnesium, and silicon ions on hole burning and the phonon sideband for borate glasses that exhibit PHB at room temperature. Hole burning was measured for the D-5(0)-F-7(0) transition of Sm2+ and the phonon sideband spectrum for the D-5(0)-F-7(0) transition of Eu3+. The hole width was closely related to local structural change, especially as it seemed to decrease with decreases in the number of nonbridging oxygens produced around the rare-earth ions. In the case of sodium aluminoborate glasses, the hole width decreased considerably with increasing alumina content. The ratio Gamma(ih)/Gamma(h) for 85B(2)O(3) . 10Al2O3 . 5Na(2)O . 1Sm(2)O(3) glass, then, was 80 at room temperature, the largest value ever reported.