Dysprosium-doped YA13(BO3)4 (YAB) crystals:: an investigation of radiative and non-radiative processes

The absorption, emission spectra and lifetime of the F-4(9/2) fluorescent level of Dy3+ in YAI(3)(BO3)(4) crystal were investigated. Energy level structure was constructed from absorption and emission spectra recorded at 5 K. The measured oscillator strengths of the transitions between the J manifolds at 300 K were compared with those derived from the Judd-Ofelt theory. The radiative transition rates and radiative lifetimes were calculated. Although there are several transitions originating in the F-4(9/2) level a major part of emission intensity is contained in the F-4(9/2) --> H-6(13/2) transition. Measurement of selfquenching of the F-4(9/2) luminescence provided a parameter characterizing an activator-activator interaction, which may be used to predict an optimal Dy concentration. The narrow and polarization dependent emission lines, relatively long lifetime of the F-4(9/2) metastable level (tau = 520 mus) and its high quantum efficiency are advantageous for low threshold laser action in both CW and pulsed operation. The emission cross-section of a potential laser line at 570 nm connected with F-4(9/2) --> H-6(13/2) transition was estimated. (C) 2003 Elsevier B.V. All rights reserved.