The influence of the Sc dopant on the transmittance of (Y, Er)AlO ceramics

High erbium content yttrium aluminum garnet (Er:YAG) and yttrium scandium aluminum garnet (Er:YSAG) ceramics have been fabricated from Er:YAG and Er:YSAG powders, respectively. The powders have been synthesized via a reverse precipitation technique, processed by uniaxial pressing followed by cold isostatic pressing, and sintered in a vacuum. TEOS (tetraethoxysilane) was used as a sintering additive. After vacuum sintering, all of the samples were processed by annealing in air to increase the transmittance and polished on both sides. The influence of the Sc 3+ content and the synthesis conditions on the microstructure and optical transparency of the Er:YAG and Er:YSAG ceramics have been investigated in detail. It has been found that changing Al 3+ for the bigger Sc 3+ ion leads to the transmittance increasing to up to 60% at a wavelength of about 1500 nm. The substitution of Al 3+ with the larger Sc 3+ in the Er:YSAG structure leads to improved elastic-plastic properties. The optical transmittance of the ceramics is affected strongly by including Sc 3+ and is increased to up to 60% at about 1.5 μm.