Cr3+ doped CaF2 transparent ceramic with effective broadband near-infrared emission

Cr 3+ has attracted much attention as activator because of the merits such as, broadband near-infrared emission and tunable emission wavelength. However, the mixed valence of Cr 3+ in some matrix materials greatly affected its luminescence. In this work, we synthesized Cr 3+ doped CaF 2 (CaF 2 :Cr 3+ ) precursor powders with a single valence of Cr 3+ ion by coprecipitation and successfully prepared CaF 2 :Cr 3+ transparent ceramics by vacuum hot-press sintering. The obtained ceramics showed high transmittance with 83% at 1200 nm and effective broadband near-infrared emission covering 680–980 nm with a full width at half-maximum (FWHM) of 130 nm. Moreover, the photoluminescence properties of ceramics were tuned by the concentration of Cr 3+ ions.