Solid-state fluorescence above 1000°C: Application to high-temperature laser thermometry

Rare-earth doped phosphors are discussed here which exhibit intense fluorescence well above 1000°C. This is a rare characteristic for solid-state materials. One immediate application for them is thermometry. For example, surface temperatures of rotating components, systems in hostile or restricted environments, and systems in environments with very high temperature backgrounds are measurable with phosphor thermographic methods. The subject phosphors, Y₂O₃:Eu, LuPO₄:Eu, YPO₄:Eu, and LuPO₄:Dy, provide the capability to extend these methods to very high temperatures. The use of pulsed ultraviolet (UV) laser activation of these phosphors leads to numerous practical application possibilities. The phosphor characteristics plus various fluorescent decay times vs temperature are shown, along with discussion of their high-temperature applications.