The influence of Pr3+ ions on the emission characteristics of Er3+-doped YSGG single crystal fibers in the 1–3 μm wavelength range

A series of 20 mol% Er3+, x mol% Pr3+: Y2.4-3xSc2Ga3O12 (Er3+, Pr3+: YSGG) single-crystal fibers (SCFs) were successfully grown by micro-pulling-down (μ-PD) method. Er3+, Pr3+: YSGG SCFs with varying concentrations of Pr3+ dopant exhibit consistent retention of the identical cubic structural space group. Under 980 nm laser diode (LD) pumping, Er3+, Pr3+: YSGG exhibits two emission bands centered at 1.6 and 2.7 μm, respectively. The incorporation of Pr3+ ions in Er3+, Pr3+: YSGG SCF materials has a negative impact on the emission peak intensity at 1.6 μm within a specific range of doping concentration, while it can relatively enhance the emission peak intensity at 2.7 μm. The lifetime of Er3+ ions at 4I13/2 is showing a significant decrease trend with increasing Pr3+ ions doping concentration. The results presented above indicate that the incorporation of Pr3+ ions increase the likelihood of particle number inversion, improving laser operation and demonstrating the desensitizing influence of Pr3+ ions. Quantitative analysis of the gain cross-section reveals a particle number inversion rate of 52.73% at approximately 2.7 μm. These findings provide valuable insights for developing applications aiming to achieve efficient and precise emission at 2.7 μm using Erbium–Praseodymium co-doped yttrium scandium gallium garnet single crystal fibers.