Assessment of conversion efficiency of Cr4+ ions by aliovalent cation additives in Cr:YAG ceramic for edge cladding |
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| Authors: | Xingtao Chen Yiquan Wu Zhongwen Lu Nian Wei Jianqi Qi Yanli Shi Tengfei Hua Qiang Zeng Wang Guo Tiecheng Lu |
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| Affiliation: | 1. College of Material Science and Technology, Nanchang University, Nanchang, China;2. College of Physics Science and Technology, Sichuan University, Chengdu, China;3. Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu, China;4. Department of Materials Science and Engineering, Kazuo Inamori School of Engineering, New York State College of Ceramics, Alfred University, Alfred, New York;5. Chengdu Fine Optical Engineering Research Center, Chengdu, China;6. Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, China |
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| Abstract: | 0.25at.% Cr:YAG ceramics were successfully fabricated as the edge cladding of Yb:YAG transparent ceramic slabs through vacuum sintering of co‐precipitated powders, using oxide additives to introduce different cations. The effects of various cation additives (Si4+, Ca2+, and Si4+ + Ca2+) on the conversion efficiency of Cr4+ ions and optical characteristics of the Cr:YAG edge cladding were investigated. Measurements of the absorption spectra of the Cr:YAG ceramics without any additives revealed 2 absorption bands centered at 430 nm and 600 nm, which imparted the sample with a green color. The introduction of only Si4+‐bearing additive did not promote the transition of Cr ions from the 3+ to 4+ state. Theoretical analysis and experimentation revealed that the addition of CaO not only enhanced the microstructure and improved the transmittance of the Cr:YAG ceramic, but also introduced vacancies that assisted in the formation of Cr4+ ions. It was determined that CaO has the same effect on the conversion efficiency of Cr4+ ions whether it is added as a single additive or in combination with SiO2. The underlying mechanisms by which these aliovalent cation additives influence the formation of Cr4+ ions and affect optical properties are discussed in detail. High quality composite ceramics with Yb:YAG transparent ceramic slabs and dark brown‐colored Cr4+: YAG ceramic edge cladding were achieved through the addition of 0.05 wt.% CaO to the edge cladding, with no interfacial effects between the 2 regions being observed. |
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| Keywords: | ceramic matrix composites electron spin resonance photoluminescence transparent ceramics yttrium aluminum garnet |
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