三维手性超材料的制作、表征及应用研究

Artificial chiral metamaterials attract lots of attentions because of their super-normal physical properties in recent years. Chiral metamaterials can achieve more excellent performance than natural chiral materials, such as micro-nano size, higher optical activity, etc, which lead to significant application on the control of polarization of light.Many studies showed that the more distinct chirality of chiral metamaterials, the stronger optical activity they have, thus researches of three-dimensional spiral structures have great significance. At present, most spiral structures were fabricated by direct laser writing method. However, it is time-consuming to fabricate samples on a large scale, which limits its potential applications..Holographic lithography, which is an efficient, low-cost and convenient method, plays an important role in fabricating photonic crystals. Based on the previous studies and latest results, we will focus on fabrication, characterization and application of three dimensional chiral metamaterials by holographic lithography. According to the results of computer simulation, we will optimize the beam setup of holographic lithography and fabricate spiral structures with different handedness, pitches and lattice constants using several photoresists. Then we will study the optical activity, circular dichroism and ellipticity of incident light in visible-infrared range, in order to gain the optimized parametric conditions for polarization stop bands. Furthermore, we will further explore the applications of three dimensional chiral metamaterials on polarization controller, circular polarizer, optical isolator, and so on. The project paves the way in fabricating and utilizing chiral metamaterials for micro-nano integrated photonic devices at the technical level.

目前人工制作具有超常物理性质的手性超材料的研究热潮不断涌起。手性超材料可以获得比天然手性材料更优异的性能，如微纳尺寸、高旋光率等，从而在对光波偏振的控制中极具应用潜力。研究表明结构本身的手性特征越强，偏振效应越强。由于具备突出的手性特征，三维螺旋结构具有更重要的研究意义。目前制备三维螺旋结构大多使用激光直写技术，成本高、速度慢，难以大面积制作。本立项基于前期研究基础和最新成果，将充分利用全息技术的灵活性和可操作性，系统开展三维手性超材料的全息光刻制作、表征及应用研究。通过光路优化设计和计算机模拟，采用不同光刻胶，制备不同旋向、不同螺距和螺径的多样化螺旋结构；并进行可见-近红外波段旋光性、圆二色性、椭圆率等的光谱测量，探究获得偏振带隙的参量条件；在此基础上开展偏振控制器、圆偏振器、光隔离器等微纳光子器件的应用研究。该项目将为手性超材料在微纳集成光子器件方面的应用提供有效地实验技术途径。

手性超材料可以获得比天然手性材料更优异的性能，如微纳尺寸、高旋光率等，从而在对光波偏振的控制中极具应用潜力，近年来获得科研工作者的青睐。研究表明结构本身的手性特征越强，偏振效应越强。由于具备突出的手性特征，三维螺旋结构具有更重要的研究意义。本项目用全息技术的灵活性和可操作性，系统开展三维手性超材料的全息光刻制作、表征及应用研究。通过光路优化设计和计算机模拟，采用不同光刻胶，制备出了不同旋向、不同螺距和螺径的多样化螺旋结构，所得结构周期尺寸可调、面积大、稳定性好。通过搭建测试系统对部分螺旋结构开展了可见-近红外波段旋光性、圆二色性、椭圆率等的光谱测量，不同手性特征结构对左旋或右旋不同偏振光具不同的透过率，得到结构对偏振光较强的调制能力，测试结果与理论计算结果相吻合。本项目成功制备了三维手性超材料，分析研究了结构与偏振光的相互作用，有望为手性超材料在微纳集成光子器件方面的应用提供有效地实验技术途径。