Preparation, spectral properties and Judd-Ofelt analysis of Ho3+:YPO4 crystal

The Ho3+:YPO4 crystal was grown by the high-temperature solution method successfully. The preparation process, crystal structures and spectroscopic properties, including polarized absorption spectra, FT-IR and Raman spectra, polarized fluorescence spectra and lifetime were characterized and analysed in detail. The absorption cross-sections at around 643 nm were calculated to be 6.93 × 10−20 cm2 for π-polarization and 2.30 × 10−20 cm2 for σ-polarization, respectively. And the spectroscopic quality factor (Ω4/Ω6) was determined to be 1.18. The full width at half the maximum (FWHM) of emission bands at the peak of 2070 nm can reach 102.43 nm for π-polarization and 83.83 nm for σ-polarization, respectively. The results show that Ho3+:YPO4 crystal is a promising laser medium which is expected to be used in around 2.0 μm.