Spectral analysis and emission properties of Ho3+: YLF in the visible-near infrared band

In order to study the spectral properties of Ho³⁺:YLiF₄ (Ho³⁺:YLF), we measured the absorption spectra f Ho³⁺:YLF crystal. The experimental and calculated electric dipole line strength are calculated based on Judd-Ofelt theory, so do other spectral parameters. In order to characterize the emission characteristics of energy level, we measured the emission spectra of Ho³⁺:YLF crystal under the pumping of lasers at 450 nm and 640 nm, and the partial emission cross-sections spectra was calculated according to the Fuchtbauer-Ladenburg theory. Moreover, the fluorescence lifetimes of 537 nm, 656 nm, 750 nm, 1195 nm and 1964 nm are measured. As far as we know, the fluorescence lifetime of 1964 nm (∼2 μm) and the emission cross-sections of ∼750 nm and ∼961 nm are confirmed for the first time. This work lays the foundation for the generation of lasing at novel wavelength on Ho³⁺:YLF crystal.