Nd~(3+):SrY_2O_4粉体的制备、结构与光谱性能研究

为探索新型激光晶体,采用固相法合成了(3 at.%)Nd~(3+):SrY_2O_4多晶,对其结构和发光性质进行了研究.对样品的X射线衍射谱进行Rietveld精修得到了样品的晶胞参数、原子位置等.在353 nm激发下,Nd~(3+):SrY_2O_4在可见波段的最强荧光峰位于419 nm,对应Nd3+的2D15/2→4I9/2跃迁.在824 nm激发下,Nd3+的4F3/2→4I11/2跃迁的荧光谱带宽约为90 nm,最强峰为1083 nm,荧光寿命为281.7μs.宽发射光谱和长的能级寿命表明,Nd~(3+):SrY_2O_4是一种很有希望的新波长激光二极管抽运超短脉冲激光材料.

Synthesis,structure and sp ectroscopic prop erties of Nd3+:SrY2O4 phosphor

In order to obtain new-type laser crystals, SrY₂O₄ is chosen as a host material. Because Y³⁺ ions in SrY₂O₄ occupy two non-equivalent sites, it might be possible to realize dual-wave laser and broadband emission at 1.06 μm by partially replacing Y³⁺ with Nd³⁺. In this work, (3 at.%) Nd³⁺ doped SrY₂O₄ phosphor is synthesized by the conventional solid state reaction. The structure and luminescence properties in the visible and near-infrared ranges are studied. The peaks in the X-ray powder diffraction pattern of (3 at.%) Nd³⁺:SrY₂O₄ can be well indexed according to ICSD#25701. The lattice parameters, atomic coordinates, atomic temperature factors etc., are obtained by the Rietveld refinement with R_p of 4.68% and R_wp of 5.91%. According to the excitation spectra in a range of 220-380 nm, it can be seen that Nd³⁺:SrY₂O₄ is efficiently excited by 353 nm which is assigned to the ⁴I_9/2→⁴D_3/2+⁴D_5/2+²I_11/2+⁴D_1/2 transition of Nd³⁺ ions. Under the 353 nm light excitation, Nd³⁺:SrY₂O₄ exhibits the strongest emission at 419 nm corresponding to the ²D1_5/2→⁴I_9/2 transition of Nd³⁺ ions. What is more, Nd³⁺:SrY₂O₄ can be excited effectively by 824 nm light, which matches well with the commercial 830 nm diode laser. When excited with 824 nm, the strongest fluorescence peak is located at 1083 nm with a wide bandwidth of about 90 nm. Compared with that at 8~K, the bandwidth in the fluorescence spectrum at 300 K is broadened because of the homogeneous broadening induced by the increase of temperature. Additionally, the peaks corresponding to the ⁴F_3/2→⁴I_11/2 transition are split into two groups at 8~K, which results from the two non-equivalent sites of Nd³⁺ ions. Compared with Nd³⁺:YAG, Nd³⁺:SrY₂O₄ has more potential applications in the tunable and ultrashort lasers. The fluorescence lifetime of the ⁴F_3/2→⁴I_11/2 transition of (3 at.%) Nd³⁺:SrY₂O₄ is 281.7 μs, which shows slight concentration quenching compared with that of (0.5 at.%) Nd³⁺:SrY₂O₄. The fluorescence lifetime of (3 at.%) Nd³⁺:SrY₂O₄ is much longer than that of (0.6 at.%) Nd³⁺:YAG which is beneficial to the energy storage. In conclusion, the wide emission band and the long decay time of 1.08 μm indicate that Nd³⁺:SrY₂O₄ is a very promising new-wavelength and ultrashort laser material pumped by laser diode.