有序“单晶”介孔薄膜的制备、负折射特性和可见光隐身性能探索研究

Ordered "single crystal" mesoporous thin films possess periodic spacial structures with the period-structure-size at 2~30 nm, which naturally is a kind of metamaterials. but their meta-properties: negative refraction and invisibility cloaking, have not been studied and reported. And the period-structure-size of the reported electromagnetic metamaterials was at the macro-scale, so the reported matamaterials just showed the invivsibility cloaking at some microwave region, instead of visible region. Whereas the more meaningful application of the invisibility cloak was focused on the visible region for humans. The "single crystal" mesoporous thin films could cope with this problem theoretically due to their nano-scale periodic units and show invisibility cloaking under visible light. So the main rearch contents in this issue are as follows: the preparations and characterizations of the "single crystal" mesoporous thin films with 3-dimentional(D) cubic, 3-D hexagonal, 2-D hexagonal(parallel pore channels and verticle pore channels) meso-structure; the preparation and characterization of the above mesoporous thin films with periodic metal nanowires or other "guests" incorporation;the theoretical calculations and analysis for the negtive refraction of the prepared thin films and the negative refractive index measurement and verification; the theoretical calculations and analysis, and the experimental measurement and verification of the visible-light invisibility cloaking of the prepared thin films for the typical objects. We hope that a kind of mesoporous thin film matamaterials which possess negative refraction and invisibility cloaking at visible region could be prepared and obtained after this study.

有序"单晶"介孔薄膜具有各种空间周期结构，周期结构尺寸2～30nm，是一种天然的纳米超材料，但是其超性能：负折射和隐身还没有研究报道。目前报道的电磁波超材料的谐振单元的周期尺寸都在宏观尺度，只在波长较长的微波段具有负折射和隐身性能，不能对可见光实现负折射和隐身，而隐身更有意义的应用是在可见光范围，具有纳米尺寸周期结构单元的介孔薄膜理论上可以解决该问题，实现材料在可见光下的负折射和隐身。本课题基于此展开研究，主要研究内容有：三维立方、三维六方、二维六方（平行孔道和垂直孔道）的空间构型的"单晶"介孔薄膜的制备和表征；周期金属纳米线等"客体"负载的上述"单晶"介孔薄膜的制备和表征；所制备薄膜的负折射响应的理论计算和分析,及其可见光负折射率的实验测量与验证；所制备薄膜对典型目标体的可见光隐身性能理论计算分析和实验测量与验证。希望通过本项目的研究，获得一种具有可见光负折射和隐身性能的介孔薄膜超材料。

纳米超材料具有周期性纳米结构单元，依靠纳米结构单元在光频段的表面等离子体耦合响应，其在光频段具有负折射、完美吸收等光学特性，可以应用于光频段的完美隐身、超衍射限成像、高效光合成、光催化等领域。通过电子束、离子束等纳米刻蚀方法成功实现了纳米超材料的实验制备（100～500 nm），但是纳米刻蚀方法仍有一些问题：如加工线宽有限、难以制备三维纳米结构等，这限制了纳米超材料的发展。本项目通过化学自组装的方法实现纳米超材料的制备；通过拉格朗日力学和统计物理方法，揭示纳米结构单元的自组装机理；根据表面等离子体光学和纳米光子学理论，研究纳米自组装体的结构参数与负折射、完美吸收等光学特性之间的关系。