Fe₂O₃ nanomaterials, as one of the transition metal oxides (TMOs) materials, have garnered attention in ultrafast photonics due to their robust third-order nonlinearity, rapid carrier recovery time, high stability, broad absorption bandwidth and straightforward preparation methods. In order to further enhance the performance of Fe₂O₃ nanomaterials, oxygen vacancy defects were introduced in the process of preparing the Fe₂O₃ nanomaterials in this paper. By characterizing the nonlinear optical properties of the prepared Fe₂O₃ nanomaterials with different surface oxygen vacancy concentrations, we found that Fe₂O₃ nanomaterials with larger oxygen vacancy content have a deeper modulation depth and the larger third-order nonlinear coefficient. It also indicated that the incorporation of oxygen vacancy defects can significantly enhance the nonlinear optical properties of Fe₂O₃ nanomaterials. Furthermore, the ultrafast carrier dynamics of Fe₂O₃ materials with varying concentrations of oxygen vacancies were investigated using femtosecond-resolved transient absorption (TA) spectroscopy, elucidating the microscopic mechanism. Finally, we inserted Fe₂O₃-based saturable absorbers into Yb- and Er-doped fiber lasers. Noise-like mode-locking operation and multi-pulse mode-locking operation are realized at 1 μm in the Yb-doped fiber laser. Besides, the conventional soliton mode-locking operations with different central wavelengths are realized within 1.5 μm band in an Er-doped fiber laser.

中文翻译：

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非晶态 Fe2O3 中的表面氧空位为超快光子学量身定制的非线性光学特性


Fe₂O₃ 纳米材料作为过渡金属氧化物 （TMO） 材料之一，因其稳定的三阶非线性、快速的载流子恢复时间、高稳定性、宽吸收带宽和简单的制备方法而受到超快光子学的关注。为了进一步提高 Fe₂O₃ 纳米材料的性能，本文在制备 Fe₂O₃ 纳米材料的过程中引入了氧空位缺陷。通过表征所制备的不同表面氧空位浓度的 Fe₂O₃ 纳米材料的非线性光学性能，我们发现氧空位含量较大的 Fe₂O₃ 纳米材料具有更深的调制深度和较大的三阶非线性系数。它还表明，氧空位缺陷的掺入可以显着增强 Fe₂O₃ 纳米材料的非线性光学性能。此外，使用飞秒分辨瞬态吸收 （TA） 光谱研究了具有不同氧空位浓度的 Fe₂O₃ 材料的超快载流子动力学，阐明了微观机制。最后，我们将基于 Fe₂O₃ 的可饱和吸收体插入掺镱和铒掺杂光纤激光器中。在 Yb 掺杂光纤激光器中，在 1 μm 处实现了类似噪声的锁模操作和多脉冲锁模操作。此外，在 Er 掺杂光纤激光器中，在 1.5 μm 波段内实现了具有不同中心波长的常规孤子锁模操作。