Enhancement of 1.54 μm emission in Er：LiNbO_3 crystal by codoping with Zn~（2＋） ions

The enhanced intensity and lengthened lifetime of 1.54 μm emission were observed for Er：LiNbO3 crystal codoped with Zn2＋ ions.The ZnO codoping led to the reduction of the green upconversion emission in Er：LiNbO3 crystals.The decay trace of the 4S3/2→4I15/2 was ob-viously nonexponential for Er：LiNbO3 codoped with 0 and 3 mol.% ZnO,but became exponential for one codoped with 6 mol.% ZnO.The OH-absorption spectra showed after codoping with Zn2＋ ions,the OH-absorption peaking position shifted from ~3495 to 3484 cm-1,and the absorption cross section decreased.These spectroscopic characteristics suggested that the improvement of 1.54 μm emission was attributed to the reduction of Er3＋ cluster sites.