Effect of microstructural features on the laser efficiency of Nd3+:Y3Al5O12 ceramics

The optical properties and microstructure of transparent Nd³⁺:Y₃Al₅O₁₂ ceramics synthesised by different reactive sintering routes are studied. It is found that the residual porosity of optical ceramics is directly related to the homogeneity of the microstructure of initial compacts, which can be estimated by the existence of particle agglomerates larger than 1 mm in initial nanopowders. A qualitative correlation is established between the residual porosity, the optical losses and the lasing slope efficiency of Nd³⁺:Y₃Al₅O₁₂ ceramics. The maximum laser efficiency (η=49%) was observed in the samples with the lowest porosity (2.3×10^-3vol%).