Boosting the branching ratio at 900 nm in Nd3+ doped germanophosphate glasses by crystal field strength and structural engineering for efficient blue fiber lasers

摘要: Fiber lasers operating at around 900 nm based on Nd3+ doped fibers have attracted intense attention recently for generating high performance pure blue laser sources by frequency doubling, which could be applied in the fields of color displays, driven solid lighting and density storage. Although several approaches been proposed to realize operation this band, example nitrogen cooling or utilizing with a special waveguide design, intrinsic low fluorescence branching ratio three-level 4F3/2 → 4I9/2 transition (900 nm) is still serious problem that limits development devices towards compactness efficiency. Here, we report crystal field strength structural engineering strategy; accordingly, not only can tuned enhancing transition, but also near-infrared (NIR) emission intensity improved six times. Furthermore, lifetimes upper level were prolonged from 124 246 μs, simultaneously. Systemically, optical analysis implies fine-tuning Stark splitting, spectroscopic quality factor (χ) dispersed state are main reasons intriguing scenario. These results will help us design glass an inherent local structure strategy efficient compact 0.9 μm fiber lasers.