Er~(3+)掺杂Na_5Lu_9F_(32)单晶体的红外光学特性

采用坩埚下降法成功地生长了Er~(3+)离子掺杂的Na_5Lu_9F_(32)(NLF)单晶体。测定了单晶体在400~2 500nm波段的吸收光谱与2.5~25μm红外波段的透过光谱。Na_5Lu_9F_(32)单晶体在400~7 150 nm宽波段范围具有好的光学透过性,在该波段的透过率达到90%。在透过光谱中几乎观察不到2.7μm中红外波段的吸收,说明单晶体中OH~-离子的含量极低。根据测定的吸收光谱,通过Judd-Ofelt理论计算了Er~(3+)在单晶体中的光学强度参数Ω_t(Ω_2=2.08,Ω_4=2.07,Ω_6=0.75),以及相应的辐射跃迁速率、荧光分支比和荧光寿命。根据Futchbauer-Ladenburg公式估算了样品的发射截面大约分别为1.42×10~(-20)cm~2(~4I_(13/2)→~4I_(15/2))和1.66×10~(-20)cm~2(~4I_(11/2)→~4I_(13/2))。在980 nm半导体激光器(LD)激发下,研究了单晶体的近红外1.5μm与中红外2.7μm的发射光谱特性。

Infrared Optical Properties of Er3+ Doped Na5Lu9F32 Single Crystal

Er³⁺ doped Na₅Lu₉F₃₂ single crystal was successfully grown by Bridgman method. The absorption spectra of the single crystal from 400 nm to 2 500 nm and the transmission characteristics from 2.5 μm to 25 μm were measured. Na₅Lu₉F₃₂ single crystal possessed high optical transmittance from 400 nm to 7 150 nm wide band, and the transmittance reached to 90%. Almost no absorption of 2.7 μm band was observed. It indicated that the content of OH^- ion was very low in the single crystal. The intensity parameters Ω_t(Ω₂=2.08, Ω₄=2.07, Ω₆=0.75) were calculated by using Judd-Ofelt theory based on the absorption spectrum. The radiative transition rates, branching ratios and radiative lifetimes were also obtained. The emission cross sections of the sample were 1.42×10^-20 cm²(⁴I_13/2→⁴I_15/2) and 1.66×10^-20 cm²(⁴I_11/2→⁴I_13/2) estimated by Futchbauer-Ladenburg formula. The emission spectra of 1.5 μm and 2.7 μm band were investigated under 980 nm LD.