Persistent spectral hole burning of Eu3+ ions in silicate glasses

Measurements of spectral hole burning have been carried out for glasses with compositions of (75 - x)SiO2. xAlO(3/2). 25NaO(1/2). 1.0EuO(3/2) (x = 0, 10, 15, 20, 25, 35) at 4.2 K. A persistent spectral hole can only be burned in silicate glass containing Al2O3 The hole burning is accompanied with no antiholes and lasts for 30 min to Ih. This phenomenon is in contrast to the hole shape and lifetime observed in an optical pumping mechanism due to Population redistribution among the hyperfine levels previously reported for Eu3+-doped silicate glass. With an increase in Al2O3 content, the hole linewidth becomes narrower and the hole depth increases. The variation in the hole linewidth can be explained in terms of the structural, changes in the aluminosilicate glass.