Dynamics of the Yb3+ to Er3+ energy transfer in LiNbO3

The energy transfer dynamics between Yb³⁺ and Er³⁺ ions in lithium niobate is investigated after ytterbium-pulsed excitation at 920 nm. The sensitisation of the LiNbO₃:Er³⁺ system with Yb³⁺ ions does not modify the lifetime of the ⁴I_13/2 erbium level (1.5-μm emission), whereas it induces a marked, concentration-dependent change in the lifetime of the ²F_5/2 (Yb³⁺) and ⁴S_3/2 (Er³⁺) multiplets (1060-nm and 550-nm emissions, respectively). The results are analysed by using the rate-equation formalism and cross-relaxation model for the energy transfer. Received: 15 October 1998 / Revised version: 24 November 1998 / Published online: 24 February 1999