Photoinduced piezooptical changes caused by microsecond CO2 Infrared lasers in lead-germanate rare earth tridoped glasses

Abstract

We have observed substantial influence of the illumination by 3.5 μs CO2 laser on the piezooptical coefficients of 59 PbO - 41 GeO 2 (in wt.%) glasses prepared with Tm2O3, Er2O3, Yb2O3 using the following concentrations (in wt.%): B-Tm2O3 (0.5)/Yb 2O3 (1.0)/Er2O3(0.5); C-Tm 2O3(0.5)/Yb2O3(1.0)/Er 2O3 O(1.0); D-Tm2O3 (0.5)/Yb 2O3 (1.0)/Er 2O3 (2.0). We have found that the maximal changes were observed for B samples that contain the lowest concentration of Er2O3. The maximal changes are observed around 360 nm near the fundamental absorption edge. There exists some correlation between the maximal intensities of the photoluminescence and the maximal piezooptical changes. The CO2 lasers cause preliminary photothermal changes. The existence of the maxima may be caused by a competition between the phonon and anharmonic phonon subsystems, which are very sensitive to the temperature.