权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Nonlinear pulse dynamics in plasmonic waveguides

等离子体波导中的非线性脉冲动力学

基本信息

批准号：
EP/K009397/1
负责人：
Andrey Gorbach
金额：
$ 6.7万
依托单位：
University of Bath
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FK009397%2F1
关键词：
Nonlinear pulse dynamics plasmonic waveguides

项目摘要

Our current understanding of light nature and its interaction with matter has allowed scientists and engineers to introduce a variety of technological solutions, which have become integral parts of everyday life. These range from laser pointers, focusing a tiny spot of light over large distances, to optical cables which replaced telegraph wires and revolutionized telecommunication industry by allowing data transmissions at incredible rates. The fundamental role in operation of any such device is played by waveguides - optical analogues of electric wires. The waveguides implement two major functions. They guide light along desired paths suppressing its natural tendency to spread and occupy all the available space. Also, by sustaining high local light intensity in the waveguide core, they trigger nonlinear response of the medium. The latter is vital to perform ultra-fast signal processing: from frequency conversion and pulse re-shaping to logical operations with signal carried by light. The present-day techniques of light guiding rely on the same principles that ensure beam focusing in an optical lens: the fact that light "prefers" to propagate in a dense medium rather than in a rarefied one. A thin wire made of a dense material, such as silica glass, surrounded, for example, by air makes a guiding structure for light. This technique, however, has the major limitation: the size of a waveguide core cannot be too small. The minimal scale here is dictated by the wavelength of light - of the order of micrometer. Being much thinner than a human hair, this is still not small enough to comply with demands of modern technology. For instance, if one is to replace all electronic components of a modern microprocessor by their optical analogues (aiming to boost the performance by a thousand times and beyond), the size of each element should be of the order of few tens of nanometers. Squeezing light this tight is a challenging task.Promising candidates to replace conventional waveguides - are the so-called plasmonic waveguides, currently being developed in research labs. They represent few nanometers thick tiny metal inclusions in a transparent dielectric background, or, vice versa, narrow grooves/wedges on a metallic surface or holes in metal films. Light guiding in such composite metal/dielectric structures is done by virtue of exciting specific waves on a surface between a metal and a dielectric. Such waves couple photons with plasma oscillations inside the metal and are called 'plasmons'. Crucially, there is no limitation as to the minimal size of a plasmonic waveguide, indeed they localize and guide light at nanometer scale.While the major guiding principles of plasmonic waveguides are well understood, little is known about different nonlinear processes with plasmons so far. The reason is that the state-of-the art theory is based on models, derived under the assumption that the material properties change on a scale comparable to or much larger than the light wavelength. Apparently, this is no longer true for plasmonic waveguide setups. It is the purpose of this research to develop appropriate theories and explore fundamentally new nonlinear processes associated with light propagation in composite nano-structures consisting of metals and dielectrics. Aiming to understand and explore novel physical effects, it will form the solid basis for future development of high performance, portable, tuneable, adaptive and reconfigurable optical devices.

我们目前对光的性质及其与物质相互作用的理解使科学家和工程师能够引入各种技术解决方案，这些解决方案已成为日常生活中不可或缺的一部分。这些范围从激光指示器，在大距离上聚焦一个微小的光点，到光缆，光缆取代了电报线，并通过以令人难以置信的速率进行数据传输而彻底改变了电信行业。在任何此类装置的操作中，波导管--电线的光学类似物--起着基本的作用。波导实现两个主要功能。它们引导光沿着所需的路径，抑制其自然扩散和占据所有可用空间的趋势。此外，通过在波导芯中维持高的局部光强度，它们触发介质的非线性响应。后者对于执行超快信号处理至关重要：从频率转换和脉冲整形到光携带信号的逻辑运算。现代的光导技术依赖于确保光束在光学透镜中聚焦的相同原理：光“更喜欢”在稠密介质中而不是在稀薄介质中传播。由致密材料（如石英玻璃）制成的细线，例如被空气包围，形成光的引导结构。然而，这种技术具有主要的限制：波导芯的尺寸不能太小。这里的最小尺度由光波长（微米量级）决定。虽然比人的头发细得多，但它仍然不够小，无法满足现代技术的要求。例如，如果要用光学模拟物取代现代微处理器的所有电子元件（旨在将性能提高一千倍或更高），则每个元件的尺寸应该是几十纳米的量级。将光压缩到如此之紧是一项具有挑战性的任务。有希望取代传统波导的候选者是所谓的等离子体波导，目前正在研究实验室中开发。它们代表透明电介质背景中几纳米厚的微小金属夹杂物，或者反之亦然，金属表面上的窄槽/楔或金属膜中的孔。这种复合金属/电介质结构中的光导是通过在金属和电介质之间的表面上激发特定波来完成的。这种波将光子与金属内部的等离子体振荡耦合，称为“等离子体激元”。最重要的是，等离子体激元波导的最小尺寸没有限制，实际上它们在纳米尺度上定位和引导光。虽然等离子体激元波导的主要指导原则已经很好地理解，但到目前为止，对等离子体激元的不同非线性过程知之甚少。原因是最先进的理论是基于模型，假设材料性质的变化与光波长相当或远大于光波长。显然，这对于等离子体激元波导设置不再是正确的。本研究的目的是发展适当的理论，并从根本上探索与光在由金属和纳米材料组成的复合纳米结构中传播相关的新的非线性过程。旨在理解和探索新的物理效应，它将为未来开发高性能，便携式，可调谐，自适应和可重构的光学器件奠定坚实的基础。