Room-temperature photochemical hole burning in Eu3+ -doped Al2O3-SiO2 glass

Persistent spectral hole burning was observed at room temperature in Eu3+-doped Al2O3-SiO2 glass. The glass was obtained by heating in hydrogen gas to reduce some Eu3+ ions to Eu2+ and the spectral hole was burned in the excitation spectrum of the 7F0→5D0 transition of Eu3+. The depth of the hole burned at 200 K was ?7% of the total excitation intensity and independent of temperature up to 350 K. A possible mechanism for hole burning is the electron transfer between the Eu3+ ions and the Al-related defect centers