Preparation of novel transparent glass–ceramics containing fluoride crystals

► Transparent glass–ceramics containing YLiF 4 nano-crystals were synthesized. ► The transmittance of the glass–ceramic with a thickness of 2 mm was more than 85% at 400 nm and as high as 95% in the infrared region. ► Rare-earth ions could be successfully incorporated into YLiF 4 nano-crystals. Transparent glass–ceramics containing YLiF 4 nano-crystals were synthesized by controlled heat-treatments of LiF YF 3 Al 2O 3 SiO 2 glass. The crystallite size estimated to be about 8 nm was much less than the wavelength of the visible light. The transmittance of the glass–ceramic with a thickness of 2 mm was more than 85% at 400 nm and as high as 95% in the infrared region. The fluorescence centered around 1000 nm was hardly observed from Er 3+-doped precursor glass under 800 nm excitation, while the emission with the Stark spitting was clearly observed for the Er 3+-doped glass–ceramic. The phonon sideband of the 7 F 0 → 5 D 2 excitation spectra of Eu 3+ reveals that Eu 3+ doped in precursor glass is in silicate network while Eu 3+ doped in the glass–ceramic is in not only silicate framework but also fluoride framework. These results indicate that rare-earth ions such as Er 3+ and Eu 3+ could be successfully incorporated into YLiF 4 nano-crystals in the glass–ceramics.