Spectroscopic properties of heavily Ho3+-doped barium yttrium fluoride crystals
Ji En-Caia), Liu Qiang†a), Nie Ming-Minga), Luo Huib), Hu Yu-Xib), Guan Zhou-Guob), Gong Ma-Lia)
       
Picture of BaY1.4 Ho0.6F8 crystal. (a) Picture of monocrystal Ho: BYF ingot (pale orange) with CZ method under the fluorescent lamp irradiation, (b) picture of cuboid Ho: BYF crystal (pale yellow) after being processed under the natural light.