High-efficiency Ho:YAG single-crystal fiber laser in-band pumped by a 1.9 μm laser diode

Abstract

We report on a 10-watt-level, efficient 2 μm Ho:YAG (0.6 at.% Ho3+ doped Y3Al5O12) single crystal fiber (SCF) laser in-band pumped by a 1.9 μm laser diode. Benefiting from the high gain of the SCF and the unique propagation features of the pump and laser beams, a maximum output power of 10.77 W is achieved with T OC = 20%, corresponding to a slope efficiency of 61.8%. The higher efficiency of 64.8% and the output power of 9.8 W are obtained with T OC = 50%. Compared to the traditional bulk crystal, wave-guiding of the pump light in the SCF can extend the gain region and thus improve the laser efficiency, which provides a simple and effective method to improve the utilization rate of the pump light even for the low-brightness laser diodes.

Fabrication and Luminescence Properties of Highly Transparent Green-Emitting Ho:Y2O3 Ceramics for Laser Diode Lighting

“…Among the rare-earth ions are Ho 3+ ions, which are used for laser action at different wavelengths, from 550 to 3900 nm. For example, Ho 3+ -ion-doped polycrystalline transparent ceramics have been widely studied in 2000 nm solid-state lasers due to their 5 I 7 → 5 I 8 energy-level transitions [12][13][14]. The Ho 3+ ion is also a suitable active ion for the up-conversion laser and many researchers have focused on up-conversion emissions (for example, highly efficient up-conversion luminescence in a Ho 3+ -Yb 3+ system) [15].…”