Fabrication and spectroscopic properties of Yb/Er:YAG and Yb, Er:YAG transparent ceramics by co-precipitation synthesis route

Transparent polycrystalline Yb/Er:YAG and Yb, Er:YAG ceramics with different Er3+ concentration were successfully fabricated by vacuum sintering co-precipitated raw powders. The structural, optical, and spectroscopic properties of the Er:YAG and Yb, Er:YAG ceramics were investigated in detail. The absorption coefficient of the Er:YAG ceramics increased with the increase of Er3+ dopant level. The absorption coefficient of Yb, Er:YAG ceramic at ~970 nm (0.967 cm−1) is nearly 4.5 times the value for Er:YAG ceramic of 0.214 cm−1. The upconversion luminescence spectra, infrared luminescence spectra, and fluorescence lifetimes of the ceramics were also studied. Results show that the intense green and red emissions located at around 523, 560 and 677 nm are attributed to the radiant transitions of 2H11/2/4S3/2 - 4I15/2 and 4F9/2 - 4I15/2 of Er3+, respectively. The infrared spectra presented many narrow emission peaks in the 1450-1700 nm regions, attributable to the 4I13/2-4I15/2 emission transition. The fluorescence lifetime of the Yb, Er:YAG ceramic (7.53 ms) is also greater than that of Er:YAG (6.67 ms). Furthermore, the underlying mechanism of the IR and visible emission bands were discussed. Experimental results provided evidence that energy transfer from Yb3+ to Er3+ can be achieved, indicating Yb, Er:YAG ceramic could be a potential lasing medium material.