We report on the first growth, spectroscopy, and visible laser operation of a single-crystal fiber (SCF) of KY3F10 (KYF) grown by the micro-pulling-down (μ-PD) method, doped with Pr3+ ions. This material has a cubic lattice, which makes it appealing for use in the industry. However, KYF crystals are considered difficult to grow with high optical quality, even with well-established methods. Neve...
