3.5 μm波段拓扑绝缘体锁模掺Er氟化物光纤激光器研究

Aiming at the application requirements of the ultra-short mid-infrared lasers in 3.5 µm waveband with shortage of nonlinear modulation components in mid-infrared region, both theoretical and experimental study of the mode-locked erbium doped fluoride fiber laser based on 2d Dirac materials topological insulator (TI) is put forward. In the project, TI materials such as Bi2Te3 will be prepared and their saturable absorption properties in mid-infrared region will be measured. The relationship between the saturable absorption parameters of the TIs and the time-domain properties of the mode-locked pulses will be uncovered. By optimizing the TIs saturable absorber preparation technology and cavity parameters, stable, high energy, and ultra-short 3.5 µm passively mode-locked erbium doped fluoride fiber laser will be obtained. This study will be made a deeper insight into the absorption properties of TIs in mid-infrared region. Moreover, it will provide the support and reference to the development of the ultrashort pulse lasers in mid-infrared region.

针对3.5 µm波段中红外超短脉冲激光的应用需求，结合中红外波段非线性调制元件匮乏的现状，开展基于二维狄拉克材料拓扑绝缘体锁模的掺Er氟化物光纤激光器理论和实验研究。实验制备碲化铋等拓扑绝缘体材料，并测量其在中红外波段的可饱和吸收特性，明确拓扑绝缘体饱和吸收强度、调制深度、非饱和损耗等参量与锁模脉冲时域性质的内在关系；优化拓扑绝缘体可饱和吸收器件制备工艺及谐振腔参数，实现稳定、高能量、超短脉冲3.5 µm波段掺Er氟化物被动锁模光纤激光输出。本研究将加深拓扑绝缘体材料在中红外波段吸收特性的理解，同时为发展中红外波段超短脉冲激光提供参考和借鉴。

3.5 µm波段中红外超短脉冲激光在环境监测、高分子聚合物加工、生物医疗、国防空间光电对抗等领域具有极其重要的应用价值和发展前景。本项目针对3.5 µm波段中红外超短脉冲激光的应用需求，结合中红外波段非线性调制元件匮乏的现状，实验研究了拓扑绝缘体碲化铋在中红外波段的可饱和吸收特性，阐明了拓扑绝缘体饱和吸收强度、调制深度、非饱和损耗等参量与锁模脉冲时域性质的内在关系，实验制备了合适参数的拓扑绝缘体可饱和吸收器件并基于其实现了3.5 µm波段掺Er氟化物光纤激光被动锁模。项目实施主要取得了以下研究成果：(1) 实验研究了拓扑绝缘体碲化铋在中红外波段的可饱和吸收特性，获得了包括饱和吸收强度、调制深度、非饱和损耗在内的可饱和吸收参数；(2) 建立了基于拓扑绝缘体锁模的掺Er氟化物光纤激光器理论模型，获得了实现3.5 µm波段稳定锁模脉冲输出的可饱和吸收参数以及腔参数；(3) 基于实验制备的拓扑绝缘体可饱和吸收器件，实现了3.5 µm波段掺Er氟化物光纤激光锁模，锁模激光的输出功率约35 mW，傅里叶变换极限下的脉冲宽度约为2 ps。课题组在Opt. Lett.、Opt. Express、IEEE Access等国际学术刊物上发表SCI论文15篇，申请国家发明专利1项，获湖南省仪器仪表学会学术年会“优秀论文一等奖”1项，湖南省仪器仪表学会科学技术奖二等奖1项，培养硕士研究生8名。