Time-resolved spectroscopy of Sm<SUP>3+</SUP> in silica and silica–Al sol–gel glasses

The fluorescence of trivalent samarium in silica glasses and silica aluminum glasses prepared by the sol gel method was studied by time resolved spectroscopy. For short time excitations mostly fluorescence from the host matrix was observed. The samarium fluorescence could be clearly seen after a longer time delay. The ratio of the intensity of the electric dipole transition to that of the magnetic dipole decreased with the time elapse after the excitation, as predicted by the theory of transition probabilities