Two mechanisms of ¹D₂ fluorescence quenching of Pr³⁺‐doped Y₂SiO₅ crystal

Abstract

Abstract In Y 2 SiO 5 :Pr 3+ crystals (0.1 at%, 0.3 at%, 0.6 at% , and 1.8 at% Pr 3+ ) characterized by the existence of two types of Pr 3+ optical centers, the energy transfer has been investigated using time‐resolved site‐selective spectroscopy techniques. The results obtained show that at certain conditions there are two different mechanisms of fluorescence quenching of the excited 1 D 2 states of Pr 3+ ions. At 0.3 at% Pr 3+ and under the excitation of 1 D 2 states as the result of 3 P 0 → 1 D 2 nonradiative relaxation, the phonon‐assisted energy transfer from 1 D 2 states of the I‐type Pr 3+ ions to the II‐type ones has been found. The nonexponential part of donor fluorescence decay was described by the law t 0.5. and the transfer efficiency exhibits a strong temperature dependence in the range of 1.5–80 K. At the direct selective excitation of the 1 D 2 states of one type Pr 3+ optical centers it was possible to observe only their own fluorescence which quenched at a concentration above 0.6 at% Pr 3+ . The donor fluorescence decay was not fit by the law t 0.5 and the quenching efficiency was characterized by the square‐loaw dependence on the concentration and a very poor dependency on the temperature. The analysis of some models allows us to assume, that in this case, the cooperative quenching of the 1 D 2 states of both type Pr 3+ optical centers can take place. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)