Abstract Nd (0.8 at.%) co-doped Yb (0.8 and 3.0 at.%):YVO4 single crystals were grown by optical floating zone technique for the first time to the best of our knowledge. The absorption spectra revealed strong absorption for π-polarization (E||c) than the σ-polarization (E┴c) for both the Yb concentrations due to anisotropy of the crystal. The estimated effective Judd-Ofelt parameters are 11.8675x10-20, 5.1577x10-20 and 7.3755x10-20 cm-2. Spectroscopic quality factor of Nd co-doped Yb:YVO4 are 0.70. which is lower than that (0.97) of Nd(1.0 at.%) doped YVO4 [ 18 ], which indicates the energy transfer from Nd ion to Yb ion inside the host matrix. The estimated emission cross-section of 4F3/2 →4I11/2 Nd transition with an excitation at 808 nm for both the concentrations of Yb is ∼ 4.0x10-19 cm2 which is almost same as estimated by Bhaumik et al. [ 18 ] for Nd:YVO4. Hence emission cross-section of 4F3/2 →4I11/2 Nd transition is not effected by Yb co-doping. Also the PL intensity of Yb at 1010 nm enhances with Yb co-doping for same Nd (0.8 at.%) this is because the Nd ion effectively excites the Yb ion in upper state. Therefore Nd ion acts as excellent sensitizer for Yb:YVO4 laser gain medium and make efficient pumping in the gain medium.

中文翻译：

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OFZ法生长Nd共掺杂Yb:YVO4单晶的光学和光谱特性研究

摘要 Nd (0.8 at.%) 共掺杂 Yb (0.8 and 3.0 at.%): YVO4 单晶是我们第一次通过光浮区技术生长。由于晶体的各向异性，吸收光谱表明对于两种 Yb 浓度，π 极化 (E||c) 的吸收强于 σ 极化 (E┴c)。估计的有效 Judd-Ofelt 参数为 11.8675x10-20、5.1577x10-20 和 7.3755x10-20 cm-2。Nd共掺杂Yb:YVO4的光谱品质因数为0.70。这低于 Nd(1.0 at.%) 掺杂的 YVO4 [18] 的 (0.97)，这表明能量从 Nd 离子转移到宿主基质内的 Yb 离子。对于两种 Yb 浓度，4F3/2 →4I11/2 Nd 跃迁的估计发射截面在 808 nm 处激发，约为 4.0x10-19 cm2，这与 Bhaumik 等人估计的几乎相同。[ 18 ] 对于 Nd:YVO4。因此，4F3/2 →4I11/2 Nd 跃迁的发射截面不受 Yb 共掺杂的影响。此外，Yb 在 1010 nm 的 PL 强度随着 Yb 共掺杂而增强，对于相同的 Nd（0.8 at.%），这是因为 Nd 离子有效地激发了处于上态的 Yb 离子。因此，Nd 离子作为 Yb:YVO4 激光增益介质的优良敏化剂，并在增益介质中进行有效泵浦。