摘要
A high-quality 1%(atom fraction)Ho^(3+):BaF_(2) crystal was successfully grown using the temperature gradient technique(TGT).The optical properties of the crystal were investigated,and continuous-wave(CW)laser operation of Ho^(3+)ions in the 2μm range was successfully demonstrated for the first time in the BaF_(2) crystal,to the best of our knowledge.Spectral parameters such asΩ_t(t=2,4,6)and radiative lifetimes were calculated and studied by the Judd-Ofelt(J-O)theory.The quality factor was calculated to be Q=6.60×10^(-20)cm^(2)·ms,and the full width at half-maximum(FWHM)was fitted to be 134.5 nm,indicating that the Ho:BaF_(2) crystal has a low laser threshold and broadband tunability.A maximum output power of 1.5 W and a slope efficiency of 29.3%were achieved by the 1908 nm fiber laser as the pumping source,with a relatively low threshold of 399 mW.Additionally,the Ho:BaF_(2) crystal achieved a tunable laser output with a bandwidth of 166.4 nm,which is the widest as reported for other 2μm band Ho-doped fluoride crystals to the best of our knowledge.These results suggest that the Ho:BaF_(2) crystal has the potential to achieve femtosecond ultrafast pulse laser output through mode-locking operation.
基金
supported by the National Key Research and Development Program of China(Nos.2022YFB3605701 and 2023YFB3507401)
the National Natural Science Foundation of China(Nos.62275198 and 52032009)。
