Room temperature persistent spectral hole burning of Eu 3+ ions doped in sol–gel derived glasses

Abstract

The persistent spectral hole-burning (PSHB) phenomenon was investigated for Eu 3+-ion-doped Al 2O 3–SiO 2 glasses prepared by the sol–gel method. The efficiency of hole burning, burned at low temperature ∼77 K, was proportionally increased with the content of OH groups surrounding the Eu 3+ ions. The proposed mechanism for hole burning is the optically activated rearrangement of the OH bonds surrounding the Eu 3+ ions. The burned hole was thermally refilled and erased above ∼200 K. On the other hand, the glass irradiated with X-rays showed PSHB up to room temperature. It is considered that the hole is formed by electron transfer between the Eu 3+ ions and the excited Eu 3+ or defect centers. The lifetime of the hole was estimated as ∼1.5×10 5 s at 200 K.