Nd3+→Yb3+ resonant energy transfer in the ferroelectric Sr0.6Ba0.4Nb2O6 laser crystal

Resonant (nonphonon-assisted) Nd3+-> Yb3+ energy transfer has been observed in Nd3+ and Yb3+ codoped Sr0.6Ba0.4(NbO3)(2) crystals. The Nd3+-> Yb3+ energy transfer in this system has been compared to those taking place in other Nd3+-Yb3+ codoped hosts, for which, in most of cases, the transfer is only possible by assistance of phonons. The resonant nature is explained as a result of both the very broad optical bands of Nd3+ and Yb3+ ions in Sr0.6Ba0.4(NbO3)(2) and the short energy gap (636 cm(-1)) between the F-4(3/2) (Nd3+) and F-2(5/2) (Yb3+) excited states. Spectroscopic data revealed that the energy transfer occurs via a nonradiative process and is dominated by an electric dipole-dipole interaction. The most relevant spectroscopic properties of the Nd3+-> Yb3+ energy transfer have been systematically investigated as a function of Yb3+ ion concentration. The energy transfer efficiency increases linearly with the Yb3+ ion concentration so that about a 50% is attained for a 10 at. % of ion acceptor concentration.