Advanced Design and Control of Active and Passive Metamaterials : from Microwaves to Optics

光通常以科学学生在学校学习的简单方式穿过透明材料。然而，物理学家最近一直在研究采用普通透明材料并以各种形状和排列插入微小金属夹杂物的可能性。当光通过这些结构时，会产生微小的电流，产生电场和磁场，改变光通过材料的方式。这种效应可能是戏剧性的，导致光减慢到每秒几米，或者以非常不寻常的方式弯曲光/所谓的负折射。这些效应在各种各样的方面都可能非常有用，而这些方面才刚刚开始被理解。打破传统衍射极限的透镜是一种可能性。另一个是“隐形斗篷”。在更普通的水平上，我们将关注的波长（mm）被期望增强蜂窝电话网络的性能，该蜂窝电话网络被设计为处理大面积、移动的应用、个人通信服务/网络、全球定位系统、广播卫星电视、卫星电话服务和汽车电子。这部分光谱中的波具有惊人的信息容量。毫米波波束的高度定向性、硬件的预期小尺寸和重量轻也是很大的优点。主要的需求是统一应用中的多个功能（例如天线/滤波器/发生器或放大器）。向更高频率发展，加上小型化，增加了带宽和信息容量。金属夹杂物比光的波长小得多，因此就光而言，具有夹杂物的材料表现为均匀的有效介质或超材料。因此，这项研究是一个协调一致的理论平台活动，旨在创造迄今为止对超材料的最佳设计和理解。我们将专注于设计解决方案，将解决一些已知的问题与超材料以及其他不知道在这个阶段。损耗是一个主要问题，我们将通过设计金属夹杂物来解决这个问题，金属夹杂物通过施加外部电流来主动控制。索尔福德将通过使用有源二极管添加到传统的环和欧米茄粒子结构来解决损耗控制和消除问题。手性或手，夹杂物将提供智能人工分子，预计有全新的性能。这些期望将需要对描述电磁场如何与物质相互作用的方程有新的更深入的了解，因此将扩展到包含非线性（即输出与输入不成比例）和非局部性（记忆）的想法。萨里将采用一种特定的建模方法，该方法将弥合微观纳米材料水平上使用的方法与先前用于宏观多层结构的技术之间的差距。他们将检查有序/无序阵列的夹杂物所设想的索尔福德。萨里将追求新的想法，使用超材料来减缓光，依赖于几何形状，而不是共振效应。帝国将解决有关等离子体的基本方面。定义的问题也需要解决，这样我们的代码将以最大的鲁棒性和可靠性编写。

Light usually passes through transparent materials in simple ways that science pupils learn at school. However, physicists have recently been examining the possibility of taking a normal transparent material, and inserting tiny metallic inclusions in various shapes and arrangements. As the light passes over these structures tiny currents are set up that generate electric and magnetic fields that modify the way the light travels through the material. The effects can be dramatic leading to slowing light to a few metres per second, or to bending light in very unusual ways / so-called negative refraction. These effects are potentially very useful in all kinds of ways that are only beginning to be understood. Lenses that break traditional diffraction limits are one possibility. An 'invisibility cloak' another. At the more mundane level, the wavelengths that we will be focussing upon (mm) are expected to enhance the performance of cellular telephone networks, designed to handle large area, mobile applications personal communication services/networks, global positioning systems, broadcast satellite television, satellite phone services and automotive electronics. Waves in this part of the spectrum have a fabulous information capacity. The highly directive nature of mm-wave beams, the predicted small size and lightweight of the hardware are also great advantages. The main desire is to unify more than one function in an application (e.g. antenna/filter/generator or amplifier). The progress towards higher frequencies, coupled to miniaturization, increases the bandwidth and information capacity. The metallic inclusions are much smaller than the wavelength of light so that as far as the light is concerned the material with inclusions behaves as a uniform effective medium, or a meta-material. The research is therefore a concerted theoretical platform activity aimed at creating the best design and understanding of metamaterials obtained so far. We will be focussing on design solutions that will address some of the known problems associated with metamaterials as well as others not known at this stage. Loss is a major issue that we will address through the design of metallic inclusions that are actively controlled by applying external currents. Salford will address loss control and elimination by using active diode additions to traditional ring and omega particle structures. Chiral, or handed, inclusions will provide smart artificial molecules that are expected to have completely new properties. These expectations will require new and deeper insights into the equations that describe how electromagnetic fields interact with matter, and so will be extended to embrace the ideas of nonlinearity (i.e. output is not proportional to input) and nolocality (memory). Surrey will adopt a specific modelling approach that will bridge the gap between methods used at the microscopic nanomaterials level and techniques previously used for macroscopic multilayered structures. They will examine ordered/disordered arrays of inclusions as conceived by Salford. Surrey will pursue new ideas of using metamaterials to slow down light that rely on geometry rather than resonance effects. Imperial will address fundamental aspects related to plasmonics. Issues of definition also need to be addressed so that our code will be written with the utmost robustness and reliability.