Optical properties of Dy3+ ion in GGG laser crystal

Abstract

High optical quality Dy3+-doped Gd3Ga5O12 (abbreviated as Dy : GGG below) crystal was grown by the Czochralski technique along the (1 1 1) orientation. The absorption spectrum, fluorescence spectrum and fluorescence decay curve of Dy : GGG have been recorded at room temperature. Based on the Judd–Ofelt (J–O) theory, the intensity parameters from the measured line strengths were determined. The J–O parameters were used to predict radiative transition probabilities, radiative lifetime and branching ratios for various excited levels of the Dy : GGG crystal. In the visible region, one intense fluorescence band was observed at 581 nm, corresponding to the 4F9/2 → 6H13/2 transition. The room-temperature fluorescence lifetime of this transition of Dy3+ ion in the GGG crystal was measured to be 0.79 ms, and the luminescent quantum efficiency of the 4F9/2 level was evaluated to be 71.4 %. The emission cross-sections of the 4F9/2 → 6H13/2 transition were estimated by the use of the Füchtbauer–Ladengurg method. The research on the emission at 581 nm indicates the possibility of using a commercially available laser diode of 353 nm as a pumping source for a solid-state yellow laser.