J. Phys. I France
Volume 1, Numéro 6, June 1991
Page(s) 881 - 899
DOI: 10.1051/jp1:1991174
J. Phys. I France 1 (1991) 881-899

Nonradiative energy transfer between Cr $\mathsf{^{3+}}$ and Nd $\mathsf{^{3+}}$ multisites in Y $\mathsf{_{3}}$Al $\mathsf{_{5}}$O $\mathsf{_{12}}$ laser crystals

J. A. Mares1, Z. Khás1, W. Nie2 and G. Boulon2

1  Institute of Physics, Czechoslovak Academy of Sciences, Na Slovance 2, 180 40 Prague 8, Czechoslovakia
2  Laboratoire de Physico-Chimie des Matériaux Luminescents URA 442 CNRS, Université Lyon I, 43 Bd du 11 Novembre 1918, 69622 Villeurbanne, France

(Received 13 December 1990, accepted in final form 26 February 1991)

The Cr $^{3+} \rightarrow$ Nd 3+ nonradiative energy transfer between various Cr 3+ and Nd 3+ multisites has been studied from both Cr 3+ and Nd 3+ fluorescence decays in good optical quality solid state laser crystals Y 3Al 5O 12 : Nd, Cr at low temperatures under site selective exicitation of Cr 3+ multisites. Various Nd 3+ decays (fast mono-exponential or double nonexponential) have been observed. The new theory of Rotman was used to fit the Nd 3+ decay curves. This theory was derived for nonuniform correlated distribution of ions in the crystal and it is an advance in comparison with the classical Inokuti-Hirayama theory for a uniform and random distribution of ions. The results show that the Nd 3+ decay curves are time broadened due to the Cr $^{3+} \rightarrow$ Nd 3+ nonradiative energy transfer and that the best fits were obtained for a nonuniform enhanced volume correlated distribution of Cr 3+ and Nd 3+ ions in Y 3AL 5O 12 laser crystals.

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