“…Selecting the proper powders, controlling their characteristics and using the appropriate sintering methodology contribute 3 to producing ceramics with high density and transmittance, pore-free microstructures and clean grain boundaries. For this reason, many publications related to laser ceramics have focused on selection of the starting powders or their synthesis [12], development of methods [13,14] and ceramic sintering processes [15,16], analysis of doping mechanisms [17,18], the function of the sintering additives [19,20] and optical properties [21,22]. However, the effects of the particle size distribution (PSD) of the starting powders and its influence on the microstructure and optical properties of RE:YAG polycrystalline ceramics obtained by SSR sintering have rarely been addressed, despite the importance of PSD has and previously published studies regarding this subject [23][24][25][26][27][28][29][30][31][32][33].…”