Host-associated luminescence from YAG optical ceramics under gamma and optical excitation

The host-associated luminescence of highly dense transparent YAG ceramic material is characterized and compared to that of a single crystal. The UV emission from the ceramic shows a red shift of almost 100 nm from its position in the single crystal, along with major differences in excitation spectrum. The disparities suggest that the two emissions have different origins in the respective materials, probably related to the differences in microstructure and preparation conditions. Alterations in the shape of the intense absorption associated with the band-to-band transition reflect profound changes in carrier distribution in the boundary region as well as a high population of defects incorporated during the grain growth.