Optical transition properties of Er3+ ions in YAl3(BO3)4 crystal

Optical absorption and emission intensities of Er3+ ions in YAl3(BO3)4 crystal have been investigated. It results in a good fit on absorption of the crystal, when the Judd–Ofelt theory of parity-forbidden electric-dipole transitions of rare earth ions on non-centrosymmetric sites is applied to Er:YAl3(BO3)4 (EYAB). Based on the Judd–Ofelt theory, the following spectral parameters have been obtained: intensity parameters Ωt, Ω2=6.54×10−20 cm2, Ω4=1.89×10−20 cm2, and Ω6=1.81×10−20 cm2, radiative transition probabilities AJ,J′, oscillator strengths PJ,J′. The radiative lifetime of levels 4I11/2, 4H9/2, and 4S3/2 are 3.105, 0.213, and 0.297 ms, respectively. The fluorescence branching ratios for the transition 4S3/2→4I15/2 is 81.0%. The value of integrated emission cross sections are also calculated. The emission transitions 4I13/2→4I15/2, 4I11/2→4I13/2, and 4S3/2→4I15/2 provide potential applications of Er:YAl3(BO3)4 as a laser material.