Impact of rare earth element clusters on the excited state lifetime evolution under irradiation in oxide glasses

Rare earth doped active glasses and fibers can be exposed to ionizing radiations in space and nuclear applications. In this work, we analyze the evolution of ²F_5/2 excited state lifetime in Yb3⁺ ions in irradiated aluminosilicate glasses by electrons and γ rays. It is found that the variation of lifetimes depends on the Yb3⁺ clusters content of the glasses for irradiation doses in the 10² - 1.5·10⁹ Gy range. In particular, glasses with high clustering show a smaller decrease in lifetime with increasing radiation dose. This behavior is well correlated to the variation in paramagnetic defects concentration determined by electron paramagnetic resonance. This effect is also observed in Yb3⁺ doped phosphate and Er3⁺ doped aluminosilicate glasses, inferring that clustering plays an important role in irradiation induced quenching.