Light unlimted - active and passive exploitation of light at the nanometre scale

光及其与物质相互作用的各种方式是我们感知周围世界的主要手段。因此，许多技术都是基于光的，这并不奇怪；例如，海底光纤构成了互联网的骨干，显示技术提供了价格合理且紧凑的水晶电视。然而，光本身有一个我们仍在努力克服的限制：光不能在其波长的一半以下成像或聚焦，即衍射极限。为了看到更小的物体，我们必须使用更短的波长。例如，蓝光使用蓝色激光（405纳米）来存储比dvd更多的信息，dvd使用波长更长的红色激光（650纳米）。今天，我们正在学习通过在光学器件中加入金属来克服这一限制。拟议的研究调查了使用金属来打破衍射极限，以创造新的技术产品，扩展计算机和互联网的功能，并为医疗保健，国防和安全提供新的传感器技术。我们常常想当然地认为光与金属相互作用的强度有多大。振荡频率为50赫兹的电（本质上是非常低频的光），其波长长达数千公里，然而，一个插在墙上的插头不过几英寸大；远低于衍射极限！在纳米尺度上构造金属表面的相对较新的能力现在允许我们使用相同的现象来突破可见光谱的衍射极限。金属通过将能量储存在电子上来实现这一点，这些电子与光一起运动，被称为表面等离子体。这种方法最近在纳米尺度上重新激活了光学研究，为更小、更紧凑的技术提供了趋势。那么，如果纳米光学与低频电具有相同的物理特性，是什么将它们区别开来呢？我认为纳米光学的典范是能够减小可见光和红外光的尺寸，从而使其首次占据与分子、固态和原子电子态相同的纳米尺度体积。在自然条件下，这种不匹配使光-物质相互作用固有地弱而缓慢。利用纳米光学，相互作用不仅变得更强、更快，而且曾经难以探测到的微弱效应也得到了显著增强。本提案的目标是加强这种弱效应，并利用它们来实现光学的新功能。任何新类型的控制都会带来警告。首先，超出衍射极限很难聚焦正常尺寸的光。其次，克服了第一个挑战后，由于金属的电阻，金属表面上的光寿命很短。我的研究计划是直接针对这些挑战的。第一个推力发展了我最近提出的一个概念，以减轻能量损失的问题，使表面等离子体变得有用。基于硅光子学，一个成熟的商业光通信架构，我可以使用成熟的技术在传统和纳米光学领域之间无缝地传输光，这对光子学技术有短期影响的潜力。第二个推力利用了我最近在表面等离子体激光器上的突破，它可以直接在纳米尺度上产生光，并通过激光作用无限期地维持它。这同时克服了纳米光学的两个挑战。虽然传统的激光器可以远距离传输光，但表面等离子体激光器内部的光是独一无二的。我想把这种光用于单分子灵敏度的光谱学。正如超高速激光作为科学家的照相机闪光灯，让我们抓拍到了大自然转瞬即逝的过程一样，表面等离子体激光将使我们能够以前所未有的分辨率探索大自然，并在单个分子的尺度上进行控制。在未触及的长度尺度上探索光学是一个令人兴奋的机会，它使我们有可能做出根本性的新发现。

Light and the various ways it interacts with matter is our primary means of sensing the world around us. It is therefore no surprise that many technologies are based on light; for example submarine optical fibres make up the backbone of the Internet and display technology delivers affordable and compact crystal clear televisions. However, light itself has a limitation that we are still trying to overcome: light cannot be imaged or focused below half its wavelength, known as the diffraction limit . To see smaller objects we must use shorter wavelengths. e.g. Blue-ray, uses blue lasers (405 nm) to store more information than DVDs, which use longer wavelength red lasers (650 nm). Today, we are learning to overcome this limit by incorporating metals in optical devices. The proposed research investigates the use of metals to shatter the diffraction limit for creating new technological products, expand the capabilities of computers and the internet and deliver new sensor technologies for healthcare, defense and security.We often take for granted just how strongly light can interact with metals. Electricity, oscillating at 50 Hz (essentially very low frequency light), has a wavelength of thousands of kilometers, yet a wall-plug is no larger than a couple of inches; well below the diffraction limit! The relatively new capability to structure metal surfaces on the nanoscale now allows us to use this same phenomenon to beat the diffraction limit in the visible spectrum. Metals do this by storing energy on the electrons that collectively move in unison with light, called surface plasmons. This approach has recently re-invigorated the study of optics at the nano-scale, feeding the trend to smaller and more compact technologies.So what sets nano-optics aside from low frequency electricity if they share the same physics? I believe the paradigm of nano-optics is the capability to reduce the size of visible and infrared light so that it can occupy the same nano-scale volume as molecular, solid state and atomic electronic states for the first time. Under natural conditions the mismatch makes light-matter interactions inherently weak and slow. With nano-optics, interactions not only become stronger and faster but weak effects once difficult to detect are dramatically enhanced. This goal of this proposal is to strengthen such weak effects and utilize them to realize new capabilities in optics.With any new type of control come caveats. Firstly, it is difficult to focus light from its normal size beyond the diffraction limit. Secondly, having overcome the first challenge, light on metal surfaces is short lived due to a metal's resistance. My research plan is geared to directly address these challenges. The first thrust develops a concept that I recently proposed to mitigate the problem of energy loss to the point where surface plasmons become useful. Building on Silicon Photonics, a well-established commercial optical communications architecture, I can use established techniques to seamlessly transfer light between the realms of conventional and nano-optics with the potential for short term impact on photonics technology. The second thrust exploits my recent breakthrough on surface plasmon lasers, which can generate light directly on the nano-scale and sustain it indefinitely by laser action. This overcomes both challenges in nano-optics simultaneously. While conventional lasers transmit light over large distances, it is the light inside surface plasmon lasers that is unique. I want to use this light for spectroscopy at single molecule sensitivities. Just as ultra-fast lasers, serving as scientists' camera flash, have given us snap shots of Nature's fleeting processes, so surface plasmon lasers will allow us to probe Nature with unprecedented resolution and control at the scale of individual molecules. Exploring optics at untouched length scales is an exciting opportunity giving us the potential to make fundamentally new discoveries.