Abstract
In this work we report the study of energy transfer between Nd
3+ and Yb
3+ ions in disordered K
5Bi
1−
x−
y
Nd
x
Yb
y
(MoO
4)
4 crystals (
x
=
0.01, 0.05, 0.1, 0.15, 0.2 and
y
=
0.1) at room temperature by using steady-state and time-resolved laser spectroscopy. The spectroscopic properties of Nd
3+ and Yb
3+ ions in these crystals make them suitable for efficient energy transfer because of the energy gap between the
4F
3/2(Nd
3+) and
2F
5/2(Yb
3+) levels which is around 300
cm
−1. The transfer efficiency obtained from the lifetimes in the single doped and codoped samples reaches 77% for the highest Nd
3+ concentration. The donor decay curves obtained under pulsed excitation have been used to establish the multipolar nature of the Nd
3+
→
Yb
3+ transfer process and the energy transfer microparameter. The nonradiative energy transfer is consistent with an electric dipole–dipole interaction mechanism assisted by energy migration among donors. Back transfer from Yb
3+ to Nd
3+ is not observed at the Yb
3+ concentration and temperature used in this work.