Revisiting the self-termination effect of erbium based near 3 μm mid-infrared lasers

Abstract

The self-termination effect of Er laser at near 3 μm is an important issue, which significantly hinders the development of Er-based near 3 μm lasers. In this work, the self-termination behavior of some low-doped laser materials is revisited and discussed through the simple Quimby model and improved Quimby model involving Boltzmann factors. An extremely lightly doped 0.3 at.% Er:CaF2 crystal is grown to verify the results of two models. And a ∼2.8 μm CW laser with the slope efficiency of 21.4% and output power of 143 mW is obtained. The two simple models provide us a pathway for fast screening some potential laser material candidates. Furthermore, the qualitative relationship between optimum doping concentration of Er laser hosts and Z’ value of the corresponding low concentration doped ones is determined. The obtained results will be helpful for growing Er laser host with suitable doping concentration to obtain excellent laser performance.