Optical Review

, Volume 14, Issue 1, pp 1–13

Influence of the Grain Boundaries on the Heat Transfer in Laser Ceramics

Authors

    • Institute for Laser ScienceUniversity of Electro-Communications
  • Hideki Yagi
    • Institute for Laser ScienceUniversity of Electro-Communications
    • Takuma WorksKonoshima Chemical Co., Ltd.
  • Takakimi Yanagitani
    • Takuma WorksKonoshima Chemical Co., Ltd.
  • Alexander Kaminskii
    • Institute of CrystallographyRussian Academy of Sciences, Crystal Laser Physics Laboratory
  • Yuri N. Barabanenkov
    • Institute of Radio Engineering and Electronics, Russian Academy of Sciences
  • Ken-Ichi Ueda
    • Institute for Laser ScienceUniversity of Electro-Communications
Invited Review Paper

DOI: 10.1007/s10043-007-0001-9

Cite this article as:
Bisson, J., Yagi, H., Yanagitani, T. et al. OPT REV (2007) 14: 1. doi:10.1007/s10043-007-0001-9

Abstract

Grain boundaries play a key role in determining several key properties of polycrystalline laser ceramics. Heat transfer measurements at low temperature constitute a good tool to probe grain boundaries. We review the results of heat transfer measurements in polycrystalline Y3Al5O12 garnets as well as Y2O3 and Lu2O3 sesquioxide materials obtained by self-energy-driven sintering of nano-particles. The average phonon mean free path in Y3Al5O12 was found to be significantly larger than the average grain size and to scale with temperature as T−2 at low temperature. Existing models describing the interaction between phonons and grain boundaries are reviewed. Correct temperature dependence of the mean free path and order of magnitude of scattering rates were found by assuming the existence of a grain boundary layer having acoustic properties different from those of the bulk. A different temperature dependence of phonon mean free path was found for the sesquioxides and was ascribed to the stronger elastic anisotropy of these materials. The thermal resistance associated to the grain boundaries of laser ceramics was found to be lower than in other dense polycrystalline ceramic materials reported in the literature.

Key words

laser ceramicsgarnetssesquioxidesgrain boundariesthermal conductivityphonons
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© The Optical Society of Japan 2007