Crystal growth, spectroscopic characterization and laser performance of Tm/Mg:LiNbO₃crystal

Abstract

A Tm, Mg co-doped LiNbO 3 crystal was grown by the traditional Czochralski method. The room-temperature absorption, photo-luminescence spectra and fluorescence lifetime of Tm 3+ ions in the crystal have been investigated. The experimental results show that the co-doped of MgO can lead to the lengthening of the measured fluorescence lifetime of the upper Tm 3+ : 3 F 4 level. Based on the Judd-Ofelt approach, the intensity parameters 2,4,6 of Tm 3+ were calculated to be 2 (6.29 × 10 −20 cm 2 ), 4 (0.54 × 10 −20 cm 2 ) and 6 (0.79 × 10 −20 cm 2 ). Other spectroscopic parameters that relate to laser performance were also obtained. Non-photorefractive continuous wave laser operation with a Tm, Mg:LiNbO 3 single crystal is demonstrated at room temperature for the first time. We obtained 1.026 W output power at 1.885 µm with a slope efficiency of near 14%, which, to the best of our knowledge, is the largest output power and the highest slope efficiency obtained for this crystal thus far. The output power was observed to be stable, and the crystal showed no sign of photorefractive damage.