Spectroscopic analysis of the Er~(3+) (4f~(11)) absorption intensities in NaBi(WO_4)_2

摘要

A spectroscopic analysis is performed on Er~(3+) (4f~(11)) ions doped in NaBi(WO_4)_2 in order to assess this material for its potential as a near infrared laser. The Judd-Ofelt model is applied to the room temperature absorption intensities of Er~(3+) (4f~(11)) in NaBi(WO_4)_2 to obtain the three phenomenological intensity parameters: Ω_2= 5.50 x 10~(-20) cm~2, Ω_4 = 1.00 x 10~(-20) cm~2, and Ω_6 = 0.71 x 10~(-20) cm~2. The intensity parameters are then used to determine the radiative decay rates (emission probabilities), radiative lifetimes, and branching ratios for the Er~(3+) transitions from the excited state multiplet manifolds to the lower-lying manifold states. Using the radiative decay rates for the Er~(3+) (4f~(11)) transitions between the corresponding excited states and the lower-lying states, the radiative lifetimes of eight excited states of Er~(3+) are determined in this host. Using the room temperature fluorescence lifetime and the radiative lifetime of the ~4I_(13/2) → ~4I_(15/2) (1.52 μm) transition of Er~(3+) in NaBi(WO_4)_2, the quantum efficiency is determined to be 84% for this laser material.