Photoluminescence of rare-earth/transition metal-doped transparent/translucent polycrystalline Al₂O₃ ceramics: A review

Transparent alumina doped with rare-earth or transition metal oxides represents a group of materials suitable for optical applications. Because of the birefringence of alumina, their preparation is demanding on the quality of starting materials, their advanced shaping, and pressure-assisted sintering. Spark plasma sintering and hot isostatic pressing have proven at achieving pore-free fine microstructures exhibiting high in-line transmission and a sufficient intensity of emitted light. The present review aims to summarize the results published on this topic, to compare them and on this base to propose other possible and/or appropriate approaches to future.