Topological insulators (TIs) exhibit exciting optical properties, which open up a new pathway to generate ultrashort pulses from fiber lasers. Layered TIs display distinct saturable absorption properties due to excited state absorption, as compared to their bulk structures. Moreover, the electronic structures of the TI films depend on the thickness of the films due to the quantum confinement of the electrons. By virtue of this, TI nanoparticles play a key role in all-fiber modelocked lasers. By tweaking the crystal structures of TIs, it is possible to generate ultrashort pulses across the visible, near-infrared, and mid-infrared wavelengths. Starting from the crystal structures and density of states calculations, how different topological insulators can be fabricated and integrated as an efficient passive saturable absorber in all-fiber modelocked lasers with the capability of producing fundamental to high-harmonic pulse generation are described clearly in this review report. Moreover, this report reviews the current state-of-art of TI-based saturable absorbers and their applications in different regimes of modelocked fiber lasers.

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拓扑绝缘体：深入回顾其在锁模光纤激光器中的应用

拓扑绝缘体 (TI) 表现出令人兴奋的光学特性，这开辟了一条从光纤激光器产生超短脉冲的新途径。由于激发态吸收，层状 TI 与其体结构相比显示出独特的可饱和吸收特性。此外，由于电子的量子限制，TI 薄膜的电子结构取决于薄膜的厚度。因此，TI 纳米粒子在全光纤锁模激光器中发挥着关键作用。通过调整 TI 的晶体结构，可以产生跨越可见光、近红外和中红外波长的超短脉冲。从晶体结构和态密度计算开始，本评论报告清楚地描述了如何制造不同的拓扑绝缘体并将其集成为全光纤锁模激光器中的有效无源可饱和吸收器，并具有产生基本到高谐波脉冲的能力。此外，本报告回顾了当前基于 TI 的可饱和吸收器的最新技术及其在不同锁模光纤激光器方案中的应用。