Spectroscopy and 2.8 µm laser operation of disordered Er:CLNGG crystals
Simone Normani, Pavel Loiko, Zhongben Pan, Е. Б. Дунина, Л.Н. Фомичева, А. А. Корниенко, Alain Braud, Weidong Chen, Uwe Griebner, Valentin Petrov, Patrice Camy
Abstract
We report on the first, to the best of our knowledge, laser operation on the 4 I 11/2 → 4 I 13/2 transition of erbium-doped disordered calcium lithium niobium gallium garnet (CLNGG) crystals with broadband mid-infrared emission properties. A 41.4 at.% Er:CLNGG continuous-wave laser generated 292 mW at 2.80 µm with 23.3% slope efficiency and a laser threshold of 209 mW. Er 3+ ions in CLNGG feature inhomogeneously broadened spectral bands ( σ SE = 1.79 × 10 −21 cm 2 at 2.79 µm; emission bandwidth, 27.5 nm), a large luminescence branching ratio for the 4 I 11/2 → 4 I 13/2 transition of 17.9%, and a favorable ratio of the 4 I 11/2 and 4 I 13/2 lifetimes, exhibiting values of 0.34 ms and 1.17 ms (for 41.4 at.% Er 3+ ), respectively.