Liu Xueyao, Yu Yanfeng, Yu Guangbin, Wang Yubo, Huang Pu, Wang Xing, Si Shuhao, Cheng Chen, Li Dengwang
Opt Express. 2024 Aug 26;32(18):31179-31192. doi: 10.1364/OE.534670.
The nonlinear optical properties of bismuth selenium telluride (BiSeTe), a few-layer two-dimensional topological insulator material, have been investigated in this work. An erbium-doped fiber laser (EDFL) based on BiSeTe (BST) nanosheets as saturable absorber (SA) was demonstrated. The BST SA with saturation intensity and modulation depth of 4.96 MW/cm and 2.45%, respectively, was obtained by mixing the layered BST nanosheets solution prepared by liquid phase exfoliation with a polyvinyl alcohol solution. On the basis of a 3.81 MHz fundamental repetition rate (RPR), seven types of high-order harmonic mode-locked (HML) at 300.2, 392.7, 424.2, 454.3, 516.9, 547.5 and 611.7 MHz were obtained, corresponding to 79th, 103rd, 111th, 119th, 135th, 144th and 160th harmonics, with the maximum 3-dB spectral width (2.31, 2.55, 2.55, 2.85, 2.96, 2.73 and 2.85 nm) and the narrowest pulse widths (1.11, 1.00, 1.00 ps, 896, 862, 935 and 895 fs), respectively. After reducing the cavity length by removing 30 m of single-mode fiber, a Q-switched operation with a maximum single pulse energy of 29.62 nJ and a tuning range of up to 81.91 kHz was obtained. The experimental results fully demonstrated that BST SA provided an important reference in the design of generating high RPR ultra-short pulses and Q-switched fiber lasers.
在本工作中，对几层二维拓扑绝缘体材料碲化铋硒（BiSeTe）的非线性光学特性进行了研究。展示了一种基于BiSeTe（BST）纳米片作为饱和吸收体（SA）的掺铒光纤激光器（EDFL）。通过将液相剥离法制备的层状BST纳米片溶液与聚乙烯醇溶液混合，获得了饱和强度和调制深度分别为4.96 MW/cm和2.45%的BST SA。在3.81 MHz的基本重复频率（RPR）基础上，获得了300.2、392.7、424.2、454.3、516.9、547.5和611.7 MHz的七种高阶谐波锁模（HML），分别对应于第79、103、111、119、135、144和160次谐波，其最大3 dB光谱宽度分别为（2.31、2.55、2.55、2.85、2.96、2.73和2.85 nm），最窄脉冲宽度分别为（1.11、1.00、1.00 ps、896、862、935和895 fs）。通过移除30 m单模光纤来减小腔长后，获得了最大单脉冲能量为29.62 nJ、调谐范围高达81.91 kHz的调Q运转。实验结果充分表明，BST SA为产生高RPR超短脉冲和调Q光纤激光器的设计提供了重要参考。
