Persistent spectral hole burning in Eu3+-doped silicate glasses codoping Al3+ and P5+ ions

Eu3+-doped SiO2, Al2O3-SiO2, and P2O5-SiO2 glasses were prepared by a sol-gel method from metal alkoxides, and their persistent spectral hole burning (PSHB) properties were investigated in relation to the local environment of the EU3+ ions in glass. Fluorescence line narrowing spectra indicated that EU3+ clustering occurred in SiO2 glass. The addition of Al2O3 or P2O5 promoted better dispersion of EU3+ in the glass matrix, though two sites for EU3+ ions seemed to exist in Al2O3-SiO2 glass. The holes were burned in the 7F(0) - D-5(0) line of the EU3+ ions using a Rhodamine 6G dye laser, the hole area of which increased proportionally with the content of hydroxyl groups. The holes that were burned by the photoinduced rearrangement of the OH bonds were thermally refilled and the barrier height of the burnt-state was determined as 0.14, 0.30, and 0.40 eV for P2O5-SiO2, SiO2, and Al2O3-SiO2 glass, respectively.