High-power lasing at ∼900  nm in Nd 3+ -doped fiber: a direct coordination engineering approach to enhance fluorescence

Lasers at ∼900nm have been of vital importance in various fields, including material processing, underwater communications, and strong-field physics. Although Nd 3+ -doped materials have been employed for the ∼900nm laser, the ∼900nm emission is in strong competition with the often more dominating ∼1060nm emission, which strongly limits the output power and applications. This paper proposes a direct coordination engineering approach, which introduces halogen to the nearest coordination of Nd 3+ in glass for increasing the bond covalency, leading to stronger emissions at ∼900nm than at ∼1060nm. Iodide-incorporated Nd 3+ -doped silica fibers show prevailing ∼900nm emission rarely observed in Nd 3+ -doped materials. Using the created fibers, a power (113.5 W) 50 times higher than the current record is accomplished based on an all-fiber structure. Our approach holds the potential for regulating the spectroscopic properties of other rare-earth-doped laser materials.