Nonradiative relaxation of rare-earth ions in YPO4 crystal

The energy gap dependence of nonradiative relaxation rate is constructed for the YPO4 crystal based on the measurement of fluorescence decay time of rare-earth ions. Parameters A and α in the expression of WNR=Ae−αΔE (energy gap law) are found to be image and image. Violet fluorescence from Nd3+:YPO4 crystal are also studied experimentally, and the corresponding radiative decay rates are calculated through the Judd–Ofelt theory.