Intense 21–42 µm broadband emission of Co/Er:PbF₂ mid-infrared laser crystal

A novel mid-infrared (MIR) laser crystal C o / E r : P b F 2 was successfully grown. The use of E r 3 + ion co-doping to sensitize a C o 2 + ion and enhance the 2.1–4.2 µm broadband MIR emission of the C o 2 + ion in a P b F 2 crystal was studied for the first time, to the best of our knowledge. The E r 3 + ion was demonstrated to be an effective sensitizer of the C o 2 + ion, making the C o / E r : P b F 2 crystal propitious to be pumped by commercialized laser diodes. Furthermore, with E r 3 + ion co-doping, the local symmetry of C o 2 + and E r 3 + ions was seriously distorted, thereby enhancing the 2.1–4.2 µm MIR emissions. This study provides a path for designing MIR laser materials with optimal performance.