Crystal growth, spectroscopic characterization and laser performance of Tm/Mg:LiNbO3 crystal

Abstract

A Tm, Mg co-doped LiNbO3 crystal was grown by the traditional Czochralski method. The room-temperature absorption, photo-luminescence spectra and fluorescence lifetime of Tm3+ 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 Tm3+:3F4 level. Based on the Judd–Ofelt approach, the intensity parameters Ω2,4,6 of Tm3+ were calculated to be Ω2 (6.29 × 10−20 cm2), Ω4 (0.54 × 10−20 cm2) and Ω6 (0.79 × 10−20 cm2). Other spectroscopic parameters that relate to laser performance were also obtained. Non-photorefractive continuous wave laser operation with a Tm, Mg:LiNbO3 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.