Control of SrF2 crystal size in transparent germanate oxyfluoride glass-ceramics through Eu2O3 doping

The development of transparent glass-ceramics is a challenging endeavor in the field of mid-infrared photonics in order to fabricate robust and optically efficient materials. In this study, the glass-forming region of the novel xGeO 2 – (100-x) (BaF 2 , SrF 2 , ½ In 2 O 3 ) system is investigated, while SrF 2 -forming glass-ceramic compositions are identified. DSC measurements upon Eu 2 O 3 doping show a decrease in the onset temperature of SrF 2 crystallization. In the meantime, both XRD and TEM acquisitions confirm a decrease in crystal size as the dopant content increases. Part of the Eu 3+ ions enter the SrF 2 crystallites, as demonstrated by steady-state and time-resolved spectroscopies. Hence, we demonstrate that europium oxide doping enables a precise control of SrF 2 nanocrystal size in the GeO 2 -BaF 2 -SrF 2 -In 2 O 3 system. Our findings open doors towards the nanostructure tailoring of SrF 2 -containing germanate glass-ceramics using rare-earth dopants for luminescence and laser applications.