Time resolved fluorescence and energy transfer analysis of Nd(3+)-Yb (3+)-Er (3+) triply-doped Ba-Al-metaphosphate glasses for an eye safe emission (1.54 microm).

This paper reports on the preparation and systematic analysis of energy transfer mechanisms in Nd(3+)-Yb(3+)-Er(3+) co-doped new series of barium-alumino-metaphosphate glasses. The time resolved fluorescence of Nd(3+) in triply doped Ba-Al-metaphosphate glasses have revealed that, Yb(3+) ions could function as quite efficient bridge for an energy transfer between Nd(3+) and Er(3+) ions. As a result, a fourfold emission enhancement at 1.54 mum of Er(3+) ions has been achieved through an excitation of (4)F(5/2) level of Nd(3+) at 806 nm for the glass having 3 mol% Yb(3+) with an energy transfer efficiency reaching up to 94%. Decay of donor (Nd(3+)) ion fluorescence has been analyzed based on theoretical models such as direct energy transfer model (Inokuti-Hirayama) and migration assisted energy transfer models (Burshtein's hopping and Yokota-Tanimoto's diffusion). The corresponding energy transfer parameters have been evaluated and discussed. Primarily, electrostatic dipole-dipole (s approximately 6) interactions are found to be responsible for the occurrence of energy transfer process in theses glasses.