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

Abstract

The effect of OH bonds on the optical absorption and persistent spectral hole burning (PSHB) properties was quantitatively analyzed in ${\mathrm{Eu}}^{3+}$-doped $\mathrm{BaO}-{\mathrm{P}}_2{\mathrm{O}}_5$ glasses. Glasses were prepared by melting the raw material at 600–$800°\mathrm{C},$ in which the OH content was changed. The hole was burned in the ${}^7{\overrightarrow{F_0}}^5{D}_0$ transition of the ${\mathrm{Eu}}^{3+}$ ions at 6 K and the dependence of the PSHB properties on temperature and time was measured. The bond covalency between ${\mathrm{Eu}}^{3+}$ 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 ${\mathrm{Eu}}^{3+}$ 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 $\sim 140\hspace{0.5em}\mathrm{meV},$ which was smaller than that for the ${\mathrm{Eu}}^{3+}$ ions doped in silica and silicate glasses.