Growth, spectroscopy and laser operation of Tm,Ho:GdScO<sub>3</sub> perovskite crystal
Kirill Eremeev, Pavel Loiko, Chengchun Zhao, Zhang-Lang Lin, Xavier Mateos, Ghassen Zin Elabedine, Patrice Camy, Alain Braud, Uwe Griebner, Valentin Petrov, Ge Zhang, Shanming Li, Ying Hang, Weidong Chen
Abstract
We report on the growth, polarized spectroscopy and first laser operation of an orthorhombic (space group Pnma ) Tm 3+ ,Ho 3+ -codoped gadolinium orthoscandate (GdScO 3 ) perovskite-type crystal. A single crystal of 3.76 at.% Tm, 0.35 at.% Ho:GdScO 3 was grown by the Czochralski method. Its polarized absorption and fluorescence properties were studied revealing a broadband emission around 2 µm. The parameters of the Tm 3+ ↔ Ho 3+ energy transfer was quantified, P 28 = 1.30 × 10 −22 cm 3 µs -1 , and P 71 = 0.99 × 10 −23 cm 3 µs -1 , and the thermal equilibrium lifetime was measured to be 3.5 ms. The crystal-field splitting of Tm 3+ and Ho 3+ multiplets in C s symmetry sites of the perovskite structure was determined by low-temperature spectroscopy and the mechanism of spectral line broadening is discussed. The continuous-wave Tm,Ho:GdScO 3 laser generated 1.16 W at ∼2.1 µm with a slope efficiency of 50.5%, a laser threshold of 184 mW, a linear laser polarization ( E || c ) and a spatially single-mode output. The Tm,Ho:GdScO 3 crystal is promising for broadly tunable and femtosecond mode-locked lasers emitting above 2 µm.