Tailoring Nd3+ luminescence characteristics by Yb3+ doping in K5Nd(MoO4)4, RbNd(WO4)2 and NdAl3(BO3)4 crystal matrices

Single crystals of three oxide compounds containing stoichiometric Nd, doped with Yb3+ ions, namely K5Nd(MoO4)4 (KNM), RbNd(WO4)2 (RNW), and NdAl3(BO3)4 (NAB) were grown from melts using Czochralski method or top seeded solution growth technique. Nd3+ fluorescence characteristics were measured in dependence of Yb3+ content and temperature. It was established that increasing Yb3+ content results in a decrease of the Nd3+ lifetime. However, the corresponding decay times values were quite different and varied from 9.5 μs for NAB up to 60 μs for KNM and 3.3 μs in RNW. Judd-Ofelt theory was applied to estimate the intrinsic lifetime of the 4F3/2 emitting level of Nd3+ for all three crystals. The calculated lifetime values are much higher than the measured values. This effect is attributed to the strong concentration quenching of the Nd3+ ions due to their high concentration in all three crystals. The possible mechanisms of the observed dependences are given.