Nd → Yb energy transfer in (Nd, Yb):Y 2O 3 transparent ceramics

Abstract

In the attempt to obtain new efficient laser systems, the Nd → Yb energy transfer characteristics in Y 2O 3 transparent ceramics were investigated. The spectral characteristics that assure the efficient resonant Nd 3+ → Yb 3+ energy transfer are presented, especially the overlap integral of the Nd 3+ 4F 3/2 → 4I 9/2 emission with the Yb 3+ 2F 7/2 → 2F 5/2 absorption in (Nd, Yb):Y 2O 3. The static spectral data reveal that the Nd 3+ → Yb 3+ energy transfer shows: a strong dependence on Yb 3+ content (less on Nd 3+), a small variation with temperature and the implication of both Yb 3+ sites in transfer, though only Nd 3+ in C 2 are active. From the analysis of Nd 3+ 4F 3/2 emission decays in double doped samples it is concluded that the Nd → Yb transfer for Nd ∼1 at.% is of direct type, through the dipole–dipole interaction with global energy transfer microparameter ∼ C DA,Nd – Yb ≈ 1 × 10 −38 cm 6 s −1 and transfer efficiencies up to 98% for rather low (∼5 at.%) Yb 3+ content.