Effect of hydroxyl bonds on persistent spectral hole burning in Eu3+-doped BaO-P2O5 glasses

The effect of OH bonds on the optical absorption and persistent spectral hole burning (PSHB) properties was quantitatively analyzed in Eu3+-doped BaO-P2O5 glasses. Glasses were prepared by melting the raw material at 600-800 degrees C, in which the OH content was changed. The hole was burned in the F-7(0)-->D-5(0) transition of the Eu3+ ions at 6 K and the dependence of the PSHB properties on temperature and time was measured. The bond covalency between Eu3+ and oxygens decreased and the hole depth linearly increased with increasing the OH content in the glass. The proposed model was that the hole was burned by the optically activated rearrangement of the OH bonds surrounding the Eu3+ ions. The hole burnt at 6 K was refilled with increasing time and temperature and an average thermal barrier height for the hole filling was similar to 140 meV, which was smaller than that for the Eu3+ ions doped in silica and silicate glasses.