Luminescence properties of Nd:YAG nanoceramics prepared by low temperature high pressure sintering method

Nd:YAG nanoceramics composed of 25 nm grains were obtained by a low temperature high pressure sintering process. Their absorption and luminescence spectra were measured. It was found that the transparency of Nd:YAG nanoceramics increases with the pressure of the fabrication process. This effect was explained in terms of reducing porosity of the ceramics with increasing the sintering pressure. It was found that the emission properties of Nd3+ ion in YAG nanoceramic were substantially different compared to its single crystalline counterpart. In particular the emission intensities and decay times strongly depends on the applied pressure. The intensity ratio of the 4F3/2 → 4I9/2 and 4F3/2 → 4I11/2 emission transitions was much higher than in a single crystal and decreased with increasing the pressure. An efficient hot emission from the 4F5/2,4H9/2 terms was observed at room temperature.