Effects of annealing on Cr-sensitized Nd:LuAG laser ceramics

This paper demonstrates that annealing can greatly improve the quality of Cr-sensitized Nd:LuAG (Cr,Nd:LuAG) ceramics. Additionally, the pumping efficiency of Nd:LuAG ceramics can be improved by co-doping with Cr3+ ions. The two broad and strong absorption bands around 600 nm ((4)A(2)- T-4(2)) and 440 nm ((4)A(2)- T-4(1)) caused by Cr3+ ions act as effective sensitizers to absorb and convert UV and visible light from a flash lamp. Furthermore, a near-infrared absorption band appears in the in-line transmittance spectra of Cr,Nd:LuAG ceramics. The XPS spectra show that this band is caused by Cr2+ ions. The effect of annealing is studied, and it is found that the near-infrared absorption could be eliminated by annealing in air at 1450 degrees C for 25 h. Furthermore, the effective fluorescence lifetime of Nd3+ ions in Cr co-doped LuAG ceramics increases from 211.28 mu s to 553.80 mu s when pumped at 440 nm. (C) 2015 Optical Society of Americ