Ho:CaYAlO4 shaped crystal fibers grown by the micro-pulling-down method and optical properties

Ho3+-doped CaYAlO4 (Ho:CALYO) crystal fibers have been successfully grown from the melt by the micro-pulling-down (μ-PD) technique for the first time. The polarized absorption spectra, fluorescence spectra and lifetime decay curves were measured at room temperature. The most intense emission of 2 at.% Ho:CALYO crystal fiber appears at 2072 nm with the full width at half maximum (FWHM) of 181.1 nm for σ polarization and at 2022 nm with FWHM of 199.4 nm for π polarization, respectively. The decay lifetimes of 5I7 state of Ho:CALYO crystal fibers with different holmium concentration were calculated. All the results show that Ho:CALYO crystal fiber has potential as a laser gain medium for ultrashort and tunable Mid-infrared laser system.