新型低损耗柔性空芯太赫兹聚合物微结构光纤的研究

Due to lack of effective teraherhz (THz) waveguide, THz signals are mainly transmitted through free space by using the reflectors and lenses fixed on the heavy platform. This method hamper the development of THz technology, especially confine the application of THz time domain spectral image system. On the basis of the previous research on microstructure fiber, this project focuses on developing the flexible low-loss hollow-core THz microstructure fiber by the use of the flexible design freedom of microstructure fiber. Theoretical model, which includes the effect of the bend on the parameters of waveguide, is set up to model the flexible hollow-core THz microstructure fiber. Novel cladding structures of hollow-core THz microstructure fiber with low loss, flexibility and resistance to deformation are proposed by exploring new material and new design. The scientific theory about fabrication process is deeply investigated to optimize the fabrication technique. An online monitor system is developed to quickly get the feedback of the quality of microstructure fiber during the fabrication process. The aim of this project is to fabricate the flexible low-loss hollow-core THz microstructure fiber which can be successfully made and have strong resistance to deformation, bend and bend orientation. We believe that this project will supply the effective method of transmitting THz signal, simply the THz system and lower the requirement of clear environment. As a result, a great progress of THz technology would be made and the THz time domain spectral image system will become minimized and be applied in the wider field.

THz有效波导的匮乏， 致使THz传输主要依赖固定在光学平台上透镜、反射镜等器件通过空间传输，严重阻碍了THz技术发展，尤其是THz时域光谱成像系统实用化的进程。本项目在前期研究积累的基础上，充分利用微结构光纤的结构设计灵活性，开展柔性低损耗空芯THz微结构光纤的研制工作。建立适用于柔性空芯THz微结构光纤分析的理论模型，将弯曲状态对波导参数的影响真实有效地引入理论模型；新材料探索与结构创新相结合，研究柔性低损耗及强容错的结构特征，创新包层结构设计；挖掘工艺背后深层次的科学问题，优化制备工艺, 建立制备实时工艺监控系统，实现制备工艺的快速反馈；最终研制出结构容错能力强、制作可行性高、低色散、可弯曲、弯曲方向角不敏感、低损耗的柔性空芯THz微结构光纤。研究成果将会有效地简化THz波传输光路，降低THz系统的复杂程度及对环境的高要求，推进THz技术尤其是时域光谱成像系统实用化及小型化的进程。

首先结合3D打印的实际建立一套THz波导弯曲传输特性分析理论模型，并在新型Kagome型空芯THz微结构光纤制备及传输特性实验研究结果的基础上建立起一套3D打印THz波导制备理论模型。在理论研究指导下，切实掌握了一套具有自主知识产权的柔性低损耗THz微结构光纤制备工艺。进而，在这些理论和实践研究成果的基础上，成功地设计研制出四种新型柔性低损耗空芯THz微结构光纤。具体性能指标如下：包含锐角微结构Kagome型空芯THz微结构光纤(低损耗区从0.8THz到1.5THz，在1.5THz处损耗低至1.31*10-4dB/m，弯曲半径大于10cm时弯曲引入的损耗可略，且对弯曲方向角不敏感)，双五边形嵌套反谐振Kagome型包层空心THz微结构光纤(在0.2至1 THz范围内平均传输损耗为0.11 cm-1，最小传输损耗在频率为0.922 THz处仅为0.012 cm-1) ，基于椭圆芯的高双折射反谐振Kagome型包层空心THz微结构光纤(在0.2至1 THz范围内平均传输损耗为0.005cm-1，模式双折射达10-3。对弯曲方向角高度灵敏，可用于弯曲方向传感)，反谐振Kagome型半椭圆管包层空心THz单模微结构光纤(在0.2到1 THz范围内平均损耗为0.078 cm-1，最小损耗在0.82THz处为0.009 cm-1。具有良好的可接续性)，超额完成了项目的研制任务指标。发表SCI及EI收录科研论文20篇，申请国家发明专利11项，超额完成10篇SCI及EI、4项国家发明专利和软件著作权的项目任务指标。基于本项目，培养博士生毕业5名、硕士生毕业10名，1名项目组骨干成员在课题进行期间晋升副教授，超额完成了本项目人才培养方面的任务指标。