Sintering additives are generally considered to be important for improving densification in fabrication of transparent ceramics. However, the sintering aids as impurities doped in the laser materials would decrease the laser output power and produce additional heat during laser operation. In this work, Yb:YAG ceramics were vacuum‐sintered without additives at different temperatures for various soaking time through using ball‐milled powders synthesized by co‐precipitation route. The densification behavior and grain growth kinetics of Yb:YAG ceramics were systematically investigated through densification curves and microstructural characterizations. It was determined that the densification in the 1500°C‐1600°C temperature range was controlled by a grain‐boundary diffusion. It is revealed that the volume diffusion is the main mechanism controlling the grain growth between 1600°C and 1750°C. Although SiO2additives can promote densification during low‐temperature sintering, the optical transmittance of Yb:YAG ceramic with no additives, sintered at 1800°C for 15 hours, reaches a maximum of 83.4% at 1064 nm, very close to the measured transmittance value of Yb:YAG single crystal. The optical attenuation loss was measured at 1064 nm in Yb:YAG transparent ceramic, to be 0.0035 cm−1, a value close to that observed for single crystals.
Tm3+‐doped mixed sesquioxide transparent ceramics are attractive candidates for the generation of robust ~2.1 μm lasers. In this paper, laser‐quality Tm:(Lu0.8Sc0.2)2O3mixed sesquioxide ceramics were shaped for the first time by gelcasting of well‐dispersed nanopowders, which were obtained using a modified coprecipitation method. The dispersibility of starting nanopowders was largely improved using alcohol‐water solvent. The rheological properties of slurries were optimized for gelcasting. We also investigated the densification behavior of the gel‐casted green compacts. In contrast to the dry‐pressing route, it was found that gelcasting could yield more homogeneous and transparent ceramics. The optical in‐line transmittance of the ceramic rod 12 mm in length was as high as 80.3% at 2090 nm. Upon pumping the ceramic rod by 796 nm diode laser, a 1.88 W
- NSF-PAR ID:
- 10370630
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Journal of the American Ceramic Society
- Volume:
- 102
- Issue:
- 8
- ISSN:
- 0002-7820
- Page Range / eLocation ID:
- p. 4919-4928
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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