Analysis of Rare Earth Dopant Distribution in Optical Ceramics

Rare Earth Dopant Distribution in YAG Laser Ceramics

and Perspectives
Georges Boulon*

Physical Chemistry of Luminescent Materials (LPCML)

University of Lyon, Claude Bernard/Lyon 1University, UMR 5620 CNRS,

Villeurbanne, France

E-mail : [e-mail]

The research activity on advanced optical materials for various applications, such as lasers, scintillators, phosphors, is greatly increasing with the availability of sintered polycrystalline ceramics, which present some advantages compared to single crystals (sizes, mechanical strength, overall production cost). Understanding their optical properties requires a detailed investigation of their microstructure, especially regarding the exact location of the required dopants (e.g. rare earth elements such as Ce³⁺, Nd³⁺ or Yb³⁺). The main goal of this lecture is to show how Transmission Electron Microscopy (TEM) useful for characterizing rare earth-doped YAG ceramics which were elaborated in different places (Shanghai Institute of Ceramics, China; Konoshima company, Japan; Faenza, CNR, Italy) from the following new observations:

- Nd³⁺ and Ce³⁺ luminescent ions strongly segregate at grain-boundaries [1-2-3],

-Yb³⁺ ions do not segregate significantly at grain-boundaries [4],

-There is a correlation between segregation of rare earth dopants in melt crystal growth and ceramic processing depending on their place in the lanthanide family [5-6],

-High Resolution and chemical spectroscopic nano-analysis results indicate the presence of amorphous and crystalline silicate phases at grains triple junction that could be one of the major scattering sources and the reason of the high optical loss in ceramics [4],

-At last, a few comments will be given on our way to detect a single luminescent ion in the YAG host by TEM technique [7].

Characterization of the distribution of rare earth ions in ceramics is especially important for the interpretation of all optical data in relationship with the real luminescent ion concentration. We will give some possible consequences on the behavior of laser ceramics.

[1] M.O. Ramirez, J. Wisdom, H. Li, Y.L. Aung, J. Stitt, G.L. Messing, V. Dierolf, Z. Liu, A. Ikesue, R.L. Byer, V. Gopalan, Optics Express, 16(2008) 5966

[2] W. Zhao, C. Mancini, D. Amans, G. Boulon, T. Epicier, Y.Min, H. Yagi, T. Yanagitani, T. Yanagida, A. Yoshikawa, Jap. J. of App. Phys. 49 (2010) 022602

[3] W. Zhao, S. Anghel, D. Amans, G. Boulon, T. Epicier, Y. Shi, X. Q. Feng, Y. B. Pan, V.Chani, A. Yoshikawa, Optical Materials 33 (2011) 684–687

[4] Laura Esposito, Thierry Epicier, Marina Serantoni, Andreana Piancastelli, Daniele Alderighi, Angela Pirri, Guido Toci, Matteo Vannini, , Sergiu Anghel, Georges Boulon

Journal of the European Ceramic Society, accepted on February 27, 2012

[5] V. I. Chani, G. Boulon, W. Zhao, T. Yanagida, A. Yoshikawa, Jpn. J. Appl.Phys. 49 (2010) 075601

[6] Georges Boulon, Thierry Epicier, Wei Zhao, Valery I. Chani, Takayuki Yanagida, Akira

Yoshikawa, Jpn. J. Appl. Phys. 50 (2011) 090207

[7] Thierry Epicier, Toyohiko Konno, Kazuhisa Sato, Georges Boulon, presented at ICL’11, June 27- July1st, 2011, Ann Arbor (USA)

*in co-operation with:

-T. Epicier, Matériaux, Ingénierie et Sciences (MATEIS), UMR 5510 CNRS, Université de Lyon,

INSA-Lyon, 69621 Villeurbanne, France

-W.Zhao, University of Science and Technology of China (USTC), Hefei, Anhui 230026, China

-A. Yoshikawa, V. Chani, T. Yanagida, IMR, Tohoku University, 2-1-1 Katahira, Sendai 983-0836, Japan

-L. Esposito, National Research Council of Italy, Institute of Science and Technology for Ceramic,

Via Granarolo 64, I-48018 Faenza (RA), Italy