Abstract:
Anti-Stokes fluorescence from the 3P0 level of impurity ions was detected in Pr3+ : Y2SiO5, Pr3+ : Lu2SiO5, and Pr3+ : Gd2SiO5 crystals non-resonantly pumped by laser radiation with a certain power density. The integrated intensity of the anti-Stokes fluorescence depends nonlinearly on the pump power density. As the atomic concentration of impurity ions was increased from 0.3% to 0.6% and 1.8%, the anti-Stokes fluorescence intensity was saturated due to the concentration quenching of the 1D2 term of the impurity Pr3+ ions. The anti-Stokes fluorescence and quenching of the 1D2 term occur due to the cross relaxation of the electronic energy of excited terms of the Pr3+ ions.