Photoluminescence of rare‐earth/transition metal‐doped transparent/translucent polycrystalline Al 2 O 3 ceramics: A review

Abstract 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.