Persistent spectral hole burning in samarium and aluminum codoped silica films prepared by RF sputtering

We observed persistent spectral hole burning in the excitation spectra of a Sm and,Al codoped SiO2 thin film at 77 and 180 K. The him was prepared fro m Sm, Al and SiO2 by RF co sputtering at a substrate temperature of 300 deg rees C, At 77 Ii, the width of the hole was 2 cm(-1) with a depth of 4% of the total intensity, while at 180 K, they were measured at 10 cm(-1) and 1% of the total intensity. The optical absorption and photoluminescence prope rties of the deposited films were changed by the use of elemental Sm and Al instead of Sm2O3 and Al2O3.