Influence of Er3+ concentration in Er:GGAG crystal on spectroscopic and laser properties

Detail spectroscopy study of erbium-doped active media is crucial for understanding of the behavior of erbium-based lasers. In this paper, for the first time, detailed study of the concentration dependence of Er3+ in garnet-based active media is presented. Wide range of novel samples Er:GGAG (26 in total) with various Er3+ concentration (0.5-38 at%), were investigated for the first time. The complete spectroscopy (absorption and emission cross-section, Raman, mid- and far-infrared transmission spectra, decay times at 4I11/2 and 4I13/2) together with Judd-Ofelt analysis and laser characteristics were measured at room temperature. Results shows strong dependence of the first excited state (4I13/2) on concentration, on the other hand, the 4I11/2 level is completely independent of the erbium doping level. The Judd-Ofelt analysis show that erbium doping has minimal effect on the structural properties of Er:GGAG. Also it is shown that Er:GGAG laser has a slope efficiency of 15.3 % (almost half of the theoretical limit) and generated maximal output power of 350 mW. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).