High-temperature persistent spectral hole burning of Eu3+-doped SiO2 glass prepared by the sol-gel process

Abstract
Persistent spectral hole burning was observed at temperatures higher than 77 K in SiO 2 glass doped with the Eu 3+ ions. The Eu 3+ -doped SiO 2 glass was prepared using the sol-gel process of Si(OC 2 H 5 ) 4 and EuCl 3 ⋅6H 2 O . A persistent spectral hole was burned in the excitation spectrum of the 7 F 0 → 5 D 0 transition of Eu 3+ using a Rhodamine 6G dye laser, of which the hole width and depth were 1.6 cm −1 and ∼20% of the total intensity, respectively, at 77 K. Hole depth decreased with increasing temperature and disappeared above ∼130 K . A possible mechanism for the hole burning is related to the local structure around Eu 3+ and the residual OH and H 2 O in the glass.