Excited-state dynamics and energy transfers in (Ca,Zr)-substituted Gd3Ga5O12single crystals doped with Cr3+and Tm3+ions

The excited-state dynamics of Cr 3+ and Tm 3+ ions in (Ca,Zr)-substituted Gd 3 Ga 5 O 12 garnets and the energy transfer mechanisms between these impurity ions were studied at room temperature under various laser excitations. The single crystals have been grown in the authors laboratory by using the Czochralski method under nitrogen and oxygen flow. The Cr 3+ to Tm 3+ energy transfers and the Tm 3+ to Tm 3+ cross-relaxation processes were analysed in detail and their efficiencies calculated as a function of the Tm 3+ concentrations.