基于反六角溶质液晶模板制备可见光快速响应负折射材料的研究

Negative index materials have been extensively studied recently due to their unique optical properties and applications including subwavelength imaging and clocking. By employing nanometer fabrication technology such as ion beam etching and electron beam etching people have already realized negative refraction in visible frequency region. But it is still very difficult for the study and application of visible light negative refraction due to the complex fabrication craft, high fabrication cost and limitations for machining area. In this application we will synthesize a new kind of reverse hexagonal liquid crystals and control its molecule alignment by electric field in order to be used as a new type template. Metallic micro structures made through this template make up the negative refraction material which can be fast controlled with the newly synthesized high double indices fast response liquid crystals. There are many advantages for this negative refraction material fabrication process such as low cost, high fabrication speed and large fabrication area. Gain materials can be distributed in such materials to improve the loss characteristic for the material because the template is liquid instead of solid. Also the template can be made into various shapes in order to fabricate various negative index optical components such as lens and prisms. This work will extremely reduce the cost and difficulty for the fabrication of negative refraction materials and make the fast controllable negative refraction materials for visible light to come into reality. All above mentioned will directly accelerate the study and application for the negative index materials in visible frequency region.

负折射材料以其在超衍射极限成像，电磁隐身以及集成光学等方面的巨大应用潜力而得到了人们广泛的研究。目前人们已经实现了可见光的负折射，但需要拥有几十纳米分辨率的加工工艺，这些加工技术往往工艺比较复杂，成本较高，并且难以制作大面积负折射材料，极大地限制着负折射材料在可见光波段的研究和应用。本申请拟合成反六角溶质液晶并用电场控制其分子排列以作为模板，在模板中生长所需要的金属微结构，并合成全新的快速高双折射率液晶，从而实现快速调控的可见光负折射材料。这种模板价格低廉，结构生长速度快，适合制作大面积负折射材料，同时此模板为液态模板，可以在其中加入增益介质用以补偿负折射材料的损耗，模板可以弯曲成任何形状用以制造各种光学器件如负折射透镜等。这项研究有助于降低负折射材料的加工难度和成本，实现快速可控的可见光负折射材料，对其在可见光波段的应用和推广有积极的促进作用。

近年来负折射材料得到了人们广泛的关注，在超衍射极限成像，电磁隐身等方面有着广泛的应用前景。本项目针对目前负折射材料领域材料制备难、损耗大以及调控难等主要问题进行了研究，这些问题极大地限制了负折射材料在可见光波段的研究和应用。本项目利用反六角溶致液晶模板通过电化学沉积的方法成功制备了银纳米线阵负折射材料。纳米线直径约10纳米，线间距约15纳米。设计并搭建了偏振相关的反射率角度谱测量实验光路，对材料的介电参数进行了测量。经实验测量，材料在405纳米到730纳米波段具有双曲型色散关系，可以实现可见光负折射。这种微结构制备方法成本低廉，材料制备速度快，适合制作大面积负折射材料，同时此模板为液态模板，模板可以弯曲成任何形状用以制造各种光学器件如负折射透镜等。本项目合成了全新的快速高双折射率液晶材料，使用该液晶材料对负折射效应进行了调控，实现了快速调控的可见光负折射材料，调控速度达到25毫秒。同时进行了利用增益介质补偿负折射材料损耗的研究并获得了预期结果。经过三年的研究工作，项目组对预定的研究内容进行了研究，达到了预期研究目标，共发表SCI论文十余篇，其中项目成员以第一作者身份在国际知名期刊Scientific Reports、Optics Express、Liquid Crystals、Optics Communications上发表相关SCI学术论文8篇，获得授权发明专利2项。本项目的研究成果有助于降低负折射材料的加工难度和成本，实现快速可控的可见光负折射材料，对其在可见光波段的应用和推广有积极的促进作用。