The luminescent quantum efficiency of Cr3+ ions in co-doped crystals of LiNbO3 : ZnO determined by simultaneous multiple-wavelength photoacoustic andluminescence experiments

In this paper, the luminescent quantum efficiency of Cr3+ ions in co-doped crystals of LiNbO3:ZnO:Cr3+ is determined by using a method based on simult aneous multiple-wavelength measurement of photoacoustic and luminescence si gnal after pulsed laser excitation. The quantum efficiency found in this la ttice was (10 +/- 4)%. This result was compared with the value found from t he study of the lifetime in terms of the temperature of the luminescent lev els involved. In this last case, two non-equivalent crystal sites were foun d for Cr3+ ions, and two fluorescence quantum yields were determined. After the estimation of the concentration of each site by electron paramagnetic resonance experiments, the averaged fluorescence quantum yield value was (9 +/- 2)% in agreement with the previous result. (C) 2001 Elsevier Science B .V. All rights reserved.