圆锥探针电场增强特性的数值模拟研究

发布时间：2018-06-14 22:40

本文选题：光存储 + 锥尖探针　；参考：《大连理工大学》2013年硕士论文

【摘要】：随着社会的不断发展,人类所掌握的知识越来越多,尤其是进入21世纪后,信息量呈现一种爆炸式的增长,速度比以往任何时候都快的多,现有的存储技术已经远远不能满足知识大爆炸的时代背景。因此,超高密度的存储技术的发展和革新已经成为了时代发展的必然要求,尤其是近场光存储,以其能够突破衍射极限限制的优点吸引了众多科研工作者的关注。首先,本文对光存储技术的历史进行了简单的介绍,并且给出了限制当前光存储发展的原因---衍射极限的概念。目前,蓝光光盘(激光为蓝光)单片容量可达到27GB。由于光的衍射极限的限制,传统的远场光存储发展的潜力十分有限。将来发展的大方向主要包括能够突破光盘平面限制的三维光学体存储和突破衍射分辨率极限的近场光学存储技术。本文对这两种存储技术分别做了介绍。其次,本文介绍了表面等离子体的基本概念。通过阐述表面等离子体的发现历程以及金属中等离子体的几种模态,使大家对于本文研究锥尖尖端电场增强特性的原理有一个详尽的了解。随后简单介绍了表面等离子体极化激元的几种激励方法。最后,本文通过使用有限元方法(Finite Element Method),详细分析了锥尖长度和入射光与锥尖轴线夹角对电场局域增强的影响。工作目的是寻求最优的锥尖形貌,使其达到锥尖尖端电场增强的最大值。在前人的工作中,人们仅仅对单独的锥尖进行研究,这样只能在一定程度上反映出锥尖增强的光学响应特性。在实际应用中,锥尖还需要一系列的配套设施,其中最不能忽视的就是记录介质的影响。本文尝试把记录介质引入到了模拟计算中,并且研究了记录介质的介电常数对电场增强的影响。这些模拟的结果不仅可以应用在超高密度的光存储上,也能应用在传感器的设计和制作上。通过一系列的计算我们得出最优解：当入射光波长为632.8nm时,Si3N4圆锥尖外包裹一层20nm厚金膜,在锥尖长度为450nm和入射光与锥尖轴线夹角为113度时,电场的局域增强最大。记录介质的存在使得圆锥尖电场增强的强度更强,并且增强的范围更加局域,光学的斑点更小,因此可以得到更小的记录点。
[Abstract]:With the continuous development of society, more and more knowledge has been grasped by human beings, especially after entering the 21st century, the amount of information presents an explosive growth, the speed is much faster than ever before. The existing storage technology is far from being able to meet the background of the Big Bang of knowledge. Therefore, the development and innovation of ultra-high density storage technology has become an inevitable requirement of the development of the times, especially the near-field optical storage, which has attracted the attention of many researchers for its advantages of breaking through the limit of diffraction. Firstly, the history of optical storage technology is briefly introduced, and the concept of diffraction limit, which limits the development of optical storage, is given. At present, the blue optical disc (laser is blue light) monolithic capacity can reach 27 GB. Due to the limitation of diffraction limit of light, the development potential of traditional far-field optical storage is very limited. The future development direction mainly includes the three-dimensional optical volume storage which can break through the optical disk plane limit and the near-field optical storage technology which can break through the diffraction resolution limit. This paper introduces the two storage technologies. Secondly, the basic concept of surface plasma is introduced. By expounding the discovery process of surface plasma and several modes of plasma in metal, we have a detailed understanding of the principle of electric field enhancement at the tip of cone tip in this paper. Then, several excitation methods of surface plasma polarizer are introduced briefly. Finally, by using the finite element method, the influence of the length of the cone tip and the angle between the incident light and the axis of the cone tip on the local enhancement of the electric field is analyzed in detail. The aim of the work is to find the optimum shape of the cone tip and make it reach the maximum of the electric field enhancement at the tip of the cone tip. In previous work, only the individual cone tip is studied, which can only reflect the optical response characteristics of cone tip enhancement to some extent. In practical application, the tapered tip also needs a series of supporting facilities, among which the influence of recording medium can not be ignored. This paper attempts to introduce the recording medium into the simulation calculation, and studies the influence of the dielectric constant of the recording medium on the electric field enhancement. These simulation results can be applied not only to ultra-high density optical storage, but also to the design and fabrication of sensors. Through a series of calculations, we obtain the optimal solution: when the incident wavelength is 632.8nm, the local electric field of Si _ 3N _ 4 is the largest when the length of the cone tip is 450nm and the angle between the incident light and the axis of the cone tip is 113C. The existence of recording medium makes the electric field enhancement of cone tip stronger, and the range of enhancement is more local, and the optical speckle is smaller, so smaller recording point can be obtained.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333.4

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