Balakrishna A, Babu S, Kumar Vinod, Ntwaeaborwa O M, Ratnakaram Y C
Department of Physics, Sri Venkateswara University, Tirupati 517 502, India; Department of Physics, University of the Free State, Bloemfontein ZA9300, South Africa.
Department of Physics, Sri Venkateswara University, Tirupati 517 502, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2017 Jan 5;170:167-73. doi: 10.1016/j.saa.2016.07.013. Epub 2016 Jul 8.
In this paper, we report the preparation and optical characterization of Pr(3+) doped lithium fluoro borate (LiFB) glasses for six different chemical compositions of Li2B4O7-BaF2-NaF-MO (where M=Mg, Ca, Cd and Pb), Li2B4O7-BaF2-NaF-MgO-CaO and Li2B4O7-BaF2-NaF-CdO-PbO. The structural and optical properties of these glasses were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), optical absorption and photoluminescence techniques. The optical absorption spectra of Pr(3+) ions in LiFB glasses have been recorded in the UV-VIS-NIR region. The optical absorption data are used to calculate various spectroscopic parameters such as Racah (E(1), E(2), E(3)) and spin-orbit interaction (ξ4f) parameters. Judd-Ofelt (J-O) (Ωλ where λ=2, 4 and 6) intensity parameters were determined by applying J-O theory, which in turn used to calculate the radiative properties such as radiative transition probabilities (A), radiative lifetimes (τR), integrated absorption cross-sections (Σ) and branching ratios (βr) for all emission levels of Pr(3+) ion in different LiFB glass matrices. By using the J-O theory and luminescence parameters, stimulated emission cross sections (σp) of prominent transitions, (3)P0→(3)H4 and (1)D2→(3)H4 of Pr(3+) ion in all LiFB glasses were calculated. (3)P0→(3)H4 possesses higher branching ratios and stimulated emission cross-sections for the Pr(3+):LiFB(Mg-Ca) glass, which can be used as a best laser excitation. The optical gain parameter (σpxτR) was noticed higher in Pr(3+):LiFB(Mg-Ca) and Pr(3+):LiFB(Cd-Pb) glasses for the transition (3)P0→(3)H4 transition, and these glasses have potential for optical amplification at 488 nm wavelength.
在本文中，我们报道了六种不同化学成分的Li2B4O7-BaF2-NaF-MO（其中M = Mg、Ca、Cd和Pb）、Li2B4O7-BaF2-NaF-MgO-CaO以及Li2B4O7-BaF2-NaF-CdO-PbO的Pr(3+)掺杂氟硼酸锂（LiFB）玻璃的制备及光学表征。通过X射线粉末衍射（XRD）、扫描电子显微镜（SEM）、傅里叶变换红外光谱（FTIR）、光吸收和光致发光技术对这些玻璃的结构和光学性质进行了表征。记录了LiFB玻璃中Pr(3+)离子在紫外-可见-近红外区域的光吸收光谱。利用光吸收数据计算了各种光谱参数，如拉卡（E(1)、E(2)、E(3)）和自旋-轨道相互作用（ξ4f）参数。通过应用贾德-奥费尔特（J-O）理论确定了Judd-Ofelt（J-O）（Ωλ，其中λ = 2、4和6）强度参数，进而用于计算不同LiFB玻璃基质中Pr(3+)离子所有发射能级的辐射性质，如辐射跃迁概率（A）、辐射寿命（τR）、积分吸收截面（Σ）和分支比（βr）。利用J-O理论和发光参数，计算了所有LiFB玻璃中Pr(3+)离子显著跃迁（3）P0→（3）H4和（1）D2→（3）H4的受激发射截面（σp）。对于Pr(3+):LiFB(Mg-Ca)玻璃，（3）P0→（3）H4具有更高的分支比和受激发射截面，可作为最佳激光激发。在Pr(3+):LiFB(Mg-Ca)和Pr(3+):LiFB(Cd-Pb)玻璃中，对于（3）P0→（3）H4跃迁，光学增益参数（σpxτR）较高，这些玻璃在488 nm波长处具有光放大潜力。
