Spark Plasma Sintering of Hexagonal Structure Yb 3+ ‐Doped Sr 5 ( PO 4 ) 3 F Transparent Ceramics

Ytterbium‐doped Sr 5 ( PO 4 ) 3 F transparent ceramics have been developed through spark plasma sintering ( SPS ) with a low sintering temperature and short dwelling time. The XRD patterns show a polycrystalline hexagonal phase, and the TEM microstructure characterization indicates that the ceramics have a narrow grain size distribution which ranges from 40 to 200 nm, with an average grain size around 150 nm. The transmittance of a 2 mm thick ceramic sample is measured to be 74% at 1000 nm by a UV –Vis– NIR spectrophotometer. Furthermore, there is a strong emission peak around 1040 nm which has a lifetime of 1.06 ms and is exhibited by a PL spectrometer with the 980 nm laser diode excitation.