Spectroscopic properties of Ho3+ ions in biaxial Lu2SiO5 crystal

A high optical quality Ho3+-doped lutetium orthosilicate laser crystal Lu2SiO5 has been grown by the Czochraski method and the accurate concentration of Ho3+ ions in the crystal was measured. The polarized absorption spectra, polarized fluorescence spectra and fluorescence decay curve of Ho3+ ions in the Lu2SiO5 crystal were measured at room temperature. Based on the Judd–Ofelt model, three effective intensity parameters were determined as: Ω2,effΩ2,eff = 4.57 × 10−20 cm2, Ω4,effΩ4,eff = 3.11 × 10−20 cm2, Ω6,effΩ6,eff = 1.42 × 10−20 cm2. The fluorescence lifetime of the 5I7 manifold for Ho3+ ions was measured to be 3.3 ms and the quantum efficiency was estimated. The polarized emission cross-sections for the 5I7 → 5I8 transition were determined by Fuchtbauer–Ladenburg formula. The good spectroscopic properties imply that Ho: Lu2SiO5 crystal is a potential laser gain medium for 2 μm lasers.