Highly stable persistent spectral hole burning in Eu3+ ions doped oxy-fluoride glasses of 30CaF2-10Al2O3-60B2O3

High temperature persistent spectral hole burning up to room temperature has been observed in Eu3+ ions doped oxy-fluoride glasses with a composition of 30CaF2-10Al2O3-60B2O3 (mol%) melted in a reducing atmosphere. The hole stability was studied through light-induced hole refilling and temperature cycling experiments. The burned holes survive thermal cycling to 300 K due to a high barrier height of 0.69 eV in the sample.