Thermomechanical properties of rare-earth-doped AlN for laser gain media: The role of grain boundaries and grain size. (March 2015)

• Record Type: Journal Article
• Authors: Wieg, A.T.; Kodera, Y.; Wang, Z.; Dames, C.; Garay, J.E.
• Is Part Of: Acta materialia. Volume 86(2015)
• Page Start: 148
• Page End: 156
• Publication Date: 2015-03
• Subjects: Transparent ceramics -- Spark plasma sintering (SPS) -- Current-activated pressure-assisted densification (CAPAD) -- Thermal conductivity -- Indent fracture toughness; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2014.11.045
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: The low thermal conductivity and poor fracture toughness of traditional laser gain media (rare-earth-doped single crystals) limits the overall power deliverable from a laser system. We present an investigation of the thermomechanical properties of a promising laser gain candidate, Tb-doped aluminum nitride (Tb:AlN). We pay special attention to the effect of the average grain size and the dopant segregation at the grain boundaries on the relevant properties: Vickers hardness, fracture toughness and thermal conductivity. We find that all properties are affected by grain boundaries and/or dopant segregation. However, the thermal conductivity is significantly more affected than the mechanical properties and therefore dominates the thermal shock figure of merit, R s . We obtained a thermal shock figure of merit in Tb:AlN more than 60 times that of the state-of-the-art laser gain material Nd:YAG.