光为什么可以告诉我们遥远的过去（上帝说要有光就有了光）

光为什么可以告诉我们遥远的过去（上帝说要有光就有了光）Not only do today's physicists understand the nature of light they are learning to control it with ever-greater precision – which means light could soon be put to work in surprising new ways. That is part of the reason why the United Nations designated 2015 as the International Year of Light.然而情况其实并没有那么糟糕，光的本质问题当然曾经在数百年里难倒了世界上最伟大的一些物理学家，但在过去的150年间，科学界在对光的本质研究方面取得了一系列的突破性进展，向世人揭示了光的神秘本质。因此，到目前的阶段，

God said，Let there be light，and there was light，What is a ray of light made of？

上帝说要有光就有了光，那么光究竟是什么?

Light is what allows us to understand the world we live in. Our language reflects this: after groping in the dark we see the light and understanding dawns.

光是我们体验这个世界的基础。我们在黑暗中摸索，直到迎来黎明——而对于光本质的理解，我们也同样经历了同样痛苦的过程。

Yet light is one of those things that we don't tend to understand. If you were to zoom in on a ray of light what would you see? Sure light travels incredibly fast but what is it that's doing the travelling? Many of us would struggle to explain.

但是，光的确是一种非常难以理解的事物：如果你用一台放大镜将一束光不断放大，你会看到什么？当然光的运动速度是极快的，但究竟是什么东西在运动？面对这样的问题，我们中的大部分人都会觉得难以回答。

It doesn't have to be that way. Light certainly has puzzled the greatest minds for centuries but landmark discoveries made over the last 150 years have robbed light of its mystery. We actually know more or less what it is.

然而情况其实并没有那么糟糕，光的本质问题当然曾经在数百年里难倒了世界上最伟大的一些物理学家，但在过去的150年间，科学界在对光的本质研究方面取得了一系列的突破性进展，向世人揭示了光的神秘本质。因此，到目前的阶段，我们已经多少知道了该如何回答这些问题。

Not only do today's physicists understand the nature of light they are learning to control it with ever-greater precision – which means light could soon be put to work in surprising new ways. That is part of the reason why the United Nations designated 2015 as the International Year of Light.

今天的物理学家们不仅理解光的本质，甚至他们还正在尝试在越来越高的精度条件下控制光的行为，这就意味着在未来某一天，光或许将以一种崭新的面貌被人类所利用。这一广袤前景也正是联合国将2015年确定为“国际光年”(International Year of Light)的原因之一。

通电的导线周围会产生磁场，铁屑在磁场的作用下发生定向排列↑

Electricity and magnetism seem like quite different things. But scientists like Hans Christian Oersted and Michael Faraday established that they are deeply entwined. Oersted found that an electric current passing through a wire deflects the needle of a magnetic compass. Meanwhile Faraday discovered that moving a magnet near a wire can generate an electric current in the wire.

电和磁看上去似乎是非常不同的两种事物。但在像奥斯特和法拉第这样的科学家的眼里，这两者是紧密关联的。奥斯特发现，放置在通电导线旁的指南针会发生偏转，而法拉第则发现，在磁场中运动的导线内部会产生电流。

Mathematicians of the day set about using these observations to create a theory describing this strange new phenomenon which they called "electromagnetism". But it wasn't until James Clerk Maxwell looked at the problem that a complete picture emerged.

当时的数学家们开始尝试基于这些观察创建一种理论来为这一被称作“电磁”(electromagnetism)新现象给出解释。但直到詹姆斯·麦克斯韦的出现，才迎来有关这一问题的完整解决。

Maxwell's contribution to science is huge. Albert Einstein who was inspired by Maxwell said that he changed the world forever. Among many other things his calculations helped explain what light is.

麦克斯韦是一位科学巨匠，他对科学作出的贡献是难以估量的。爱因斯坦同样是受到了麦克斯韦的启发，他曾表示，麦克斯韦永远地改变了这个世界。抛开他其他方面的成就不谈，麦克斯韦的计算帮助揭示了光的本质。

Maxwell showed that electric and magnetic fields travel in the manner of waves and that those waves move essentially at the speed of light. This allowed Maxwell to predict that light itself was carried by electromagnetic waves – which means light is a form of electromagnetic radiation.

麦克斯韦的工作首次从理论上证明了，电和磁场的运动都具有波的性质，并且这种波的运动速度基本上是光速。通过这一结论，麦克斯韦进一步推断光本身可能也正是由电磁波所携带的——这就意味着光是一种电磁辐射。

麦克斯韦于1861年拍下了世界上第一张彩色照片↑

In the late 1880s a few years after Maxwell's death German physicist Heinrich Hertz became the first to formally demonstrate that Maxwell's theoretical concept of the electromagnetic wave was correct.

到了1880年代，就在麦克斯韦离世之后不久，德国物理学家赫兹首次证明，麦克斯韦关于电磁波的理论概念是正确的。

"I am convinced that if Maxwell and Hertz had lived into the Nobel prize era they would have surely shared one " says Graham Hall of the University of Aberdeen in the UK – where Maxwell worked in the late 1850s.

1850年代，麦克斯韦曾在英国阿伯丁大学工作。而在今天，同样在该校工作的物理学家格雷汉姆·豪尔(Graham Hall)指出：“我确信，如果麦克斯韦和赫兹能够活到诺贝尔奖颁发的年代，他们两人将毫无疑问的分享一次诺贝尔奖。”

Maxwell holds a place in the annals of light science for another more practical reason. In 1861 he unveiled the first durable colour photograph produced using a three-colour filter system that still forms the basis of many forms of colour photography today.

事实上，麦克斯韦在光学领域的重要贡献还包括一些更为具体的原因，比如他在1861年拍摄了世界上第一张彩色照片。他拍摄这张照片使用的三色滤镜系统至今仍然是很多彩色照相技术的基础。

Still the idea that light is a form of electromagnetic radiation may not mean too much. But this idea helps to explain something that we all understand: light is a spectrum of colours.

光是一种电磁辐射，这一概念本身或许并不意味着很多东西。但这一观点将帮助我们解释一种我们都已经知晓的现象：光是由不同的颜色组成的。

我们都被教育说，彩虹里有7种不同的颜色↑

This is an observation that goes back to the work of Isaac Newton. We see this colour spectrum in all its glory whenever a rainbow hangs in the sky – and those colours relate directly to Maxwell's concept of electromagnetic waves.

这项发现还要追溯到牛顿的时代。而在日常生活中，雨后的彩虹就是光的多色本质的天然展示——而光的这些颜色便与麦克斯韦的电磁波理论直接相关。

The red light along one edge of the rainbow is electromagnetic radiation with a wavelength of about 620 to 750 nanometres; the violet light along the opposite edge is radiation with a wavelength of 380 to 450nm.

位于彩虹一端的红色光对应的是波长在620~750nm之间的电磁波辐射；而紫色光对应的则是波长在380~450nm之间的电磁波辐射。

But there is far more to electromagnetic radiation than these visible colours. Light with wavelengths slightly longer than the red light we see is called infrared. Light with wavelengths slightly shorter than violet is called ultraviolet.

但在这些具体可见的颜色之外，还存在着比这多得多的电磁辐射。波长比我们看到的红光更长的光被称作红外光，而波长比我们看到的紫色光更短的光则被称为紫外光。

Many animals can actually see ultraviolet and so can some people says Eleftherios Goulielmakis of the Max Planck Institute of Quantum Optics in Garching Germany. In some circumstances even infrared is visible to humans. Perhaps this is why it's not uncommon to see both ultraviolet and infrared described as forms of light.

德国马克斯普朗克量子光学研究所的科学家埃利弗舍瑞奥斯-古尔利马基斯(Eleftherios Goulielmakis)表示，很多动物能够看到紫外光，甚至有一部分人也可以。而在某些特定的情况下，人眼甚至能够察觉红外光。这可能也体现在了我们的语言习惯中：你会发现，在英语中我们将红外光(infrared light)和紫外光(ultraviolet light)称为“光”(light)。

Curiously though go to even longer – or shorter – electromagnetic wavelengths and we stop using the word "light".

但对于那些波长比红外光更长，或是比紫外光更短的电磁波，我们就不再将它们以“光”来命名了。

我们眼睛能够看到的可见光实际上只不过是整个电磁波中非常狭窄的一小段区域 ↑

Beyond ultraviolet electromagnetic wavelengths can go shorter than 100nm. This is the realm of X-rays and gamma rays. You won't often hear X-rays described as a form of light.

比如波长比紫外光更短的（小于100nm）是X射线(X-ray)和伽马射线(gamma ray)。X射线不会被描述成光的形式。

"A scientist wouldn't say 'I'm shining X-ray light on the target'. They would say 'I'm using X-rays' " says Goulielmakis.

古尔利马基斯举例说：“一位医生会说，我要用‘X-ray’(X射线)照射目标，他不会说我要用‘X-ray light’(X射线光)”。

Meanwhile go beyond infrared and electromagnetic wavelength stretches to 1cm and even up to thousands of kilometres. These electromagnetic waves are given familiar names like microwaves and radio waves. It may seem strange to think of the radio waves used in broadcasting as light.

在另一端，电磁波的波长也可以远远超出红外波段，其波长达到1厘米甚至是数千公里。这样的电磁波拥有一些我们非常熟悉的名字：微波和无线电波。当然，对于普通的民众来说，他们收听广播电台的无线电波竟然和光本质上是同一类东西，这一事实会让他们觉得难以理解。

"There is no real physical difference between radio waves and visible light from the point of view of physics " says Goulielmakis. "You would describe them with exactly the same sort of equations and mathematics." It's only our everyday language that treats them as different.

古尔利马基斯表示：“从物理学的角度来看，无线电波和可见光之间并没有什么区别。描述它们的方程式和数学方式是完全一样的。”事实上，正是因为我们的日常语言中给予了它们不同的名字，才造成似乎两者是有差异的这种错觉。

So we have another definition of light. It is the very narrow range of electromagnetic radiation that our eyes can actually see. In other words light is a subjective label that we only use because our senses are limited.

这样，我们对于光就有了另一种定义——它是电磁波中非常窄的一个波段范围，也就是我们人眼能够感知到的电磁波波段范围。换句话说，我们所谓的“光”其实是一个非常主观的概念：只有我们看得到的电磁波才是光，我们看不到的就不是。

For more evidence of just how subjective our concept of light is think back to the rainbow.

而我们想知道我们对于光的概念是多么主观，让我们再次回到彩虹的话题。

彩虹能让我们看到可见光波段中不同波长的色光↑

Most people learn that the spectrum of light contains seven main colours: red orange yellow green blue indigo and violet. We are even given handy mnemonics and songs to remember them.

我们中的大多数人都知道彩虹有7种主要颜色，即所谓赤橙黄绿青蓝紫，在不同文化中，我们都创造出一些小口诀甚至歌曲来帮助我们记住这些颜色。

Look at a strong rainbow and you can probably convince yourself that all seven colours are on show. However Newton himself struggled to see them all.

当你观察清晰呈现的彩虹，你或许会让自己确信，的确存在这样的七种不同颜色。然而，当年的牛顿却发现自己难以看到全部这7种颜色。

In fact researchers now suspect that he only divided the rainbow into seven colours because the number seven was so significant in the ancient world: for instance there are seven notes in a musical scale and seven days in a week.

事实上，研究人员现在倾向于认为，之所以牛顿将光线分成了7种不同的颜色，仅仅是因为“7”这个数字在西方文化中占有特殊地位，如七声音阶，以及一周内的天数。

Maxwell's work on electromagnetism took us past all this and showed that visible light was part of a larger spectrum of radiation. It also seemed to finally explain the nature of light.

而麦克斯韦的工作则带领我们完全超越了这一高度，证明了可见光只是更宽广尺度上电磁波的一部分。这基本上可以说是最终解答了光的本质问题。

光在镜面间遵循严格的入射和反射路径↑

For centuries scientists had been trying to pin down the actual form that light takes at a fundamental scale as it travels from a light source to our eyes.

但在另一个方面，科学家们数百年来也一直致力于想要弄清楚，从最基础的层面上，光究竟是以何种方式存在并传播的？

Some thought that light travelled in the form of waves or ripples either through air or a more nebulous "ether". Others thought this wave model was wrong and imagined light as a stream of tiny particles.

一部分科学家认为光的形式有点类似波或水里的波纹，它可能是借助空气或是另一种难以捉摸的神秘物质“以太”来进行传播的。但另外一些科学家则认为这种看法是错误的，他们指出，光应当是一束粒子流。

Newton preferred this second option particularly after a series of experiments he performed using light and mirrors.

牛顿更倾向于第二种理论，即光的粒子说，尤其是在他使用光和镜子进行了一系列的相关实验之后，牛顿更加坚信光是粒子流的理论正确性。

He realised that rays of light obeyed very strict geometric rules. Shine a ray against a mirror and it bounced off in exactly the same way a ball would if it were thrown against the mirror. Waves don't necessarily move in such predictable straight lines he reasoned so light must be carried by some form of tiny weightless particles.

牛顿在实验中注意到，光的传播遵循严格的几何法则。如果你正对一面镜子并射出一束光，它一定会原路反射回来，这跟你射出一个小球击中镜子之后反弹回来是完全一致的。牛顿认为如果光是波，不应当会具备这种粒子的特性。据此，牛顿推断光必定是由某种非常微小的，没有质量的粒子所组成的。

The trouble is there was equally compelling evidence that light is a wave.

但这一理论存在一个严重的问题，那就是同样有实验证据，证明光具有波的特性。

光的双缝实验以及得到的明暗干涉条纹，强有力的证明了光具有波的性质↑

One of the most famous demonstrations of this came in 1801. Thomas Young's "double slit experiment" is the sort of experiment anyone can replicate at home.

其中最著名的一项实验是在1801年进行的。英国物理学家托马斯·杨(Thomas Young)开展了他著名的“双缝实验”，这个实验在物理学上占据极其重要的地位，并且实验的原理非常简单，每个人在家里都可以自己进行。

Take a sheet of thick card and carefully make two thin vertical slits through it. Then get a "coherent" light source which only produces light of a particular wavelength: a laser will do nicely. Now shine the light through the two slits onto another surface.

具体的过程是这样的：你需要一张厚纸板，随后非常小心地在它上面划出两道细缝。随后准备一个“纯粹”的光源，也就是只会产生特定波长光线的光源，激光则是最理想的。然后将光源对准纸板上的这两道狭缝，并使其在狭缝后的另一个表面上成像。

On that second surface you might expect to see two bright vertical lines where some of the light has passed through the two slits. But when Young performed the experiment he saw a sequence of light and dark lines rather like a bar code.

在置于狭缝纸板背后的另一个平面上，你心里的预期应该是会看到两道明亮的光带，因为来自光源的光线会分别穿过两道狭缝并投射到后方的平面上。然而，托马斯·杨发现，情况似乎有点诡异，他看到的并非两道细细的光带，而是一系列明暗相间的条纹，就像一条超市用的条形码。

通过狭缝之后，原本平行的光线变成类似水波的形态↑

When the light passes through the thin slits it behaves in the same way that water waves do when they pass through a narrow opening: they diffract and spread out in the form of hemispherical ripples.

当光线通过狭缝时，其表现出来的行为与水波穿过狭窄开口时表现出的性质基本一致：它会发生衍射并形成半球状传播的波。

Where the "light ripples" from the two slits hit each other out of phase they cancel out forming dark bars. Where the ripples hit each other in phase they add together to made bright vertical lines.

而在双缝实验中，当“光波”穿过两道狭缝并彼此相遇，且波峰面对对方的波谷时，它们相互抵消，形成暗带；而当波峰与波峰相遇时，它们相互叠加，从而形成亮带，于是，明暗相间的“条形码”条纹便出现了。

Young's experiment was compelling evidence of the wave model and Maxwell's work put the idea on a solid mathematical footing. Light is a wave.

托马斯·杨的理论无可争议地证明了光波理论的正确性，在加上麦克斯韦的工作已经在数学上为光是一种波的理论奠定了坚实的数学基础，于是科学家们大舒了一口气：终于尘埃落定了，光是一种波！

But then came the quantum revolution.

但噩梦还没结束，量子革命开始了！

白炽灯泡利用能够产生电磁辐射的材料制成↑

In the second half of the nineteenth century physicists were trying to understand how and why some materials absorbed and emitted electromagnetic radiation better than others.

在19世纪下半页，物理学家们想要弄清楚一个问题，那就是为何在吸收和辐射电磁波方面，某些材料的性能要比其他材料更好。

That may sound a bit niche but the electric light industry was emerging at the time so materials that could emit light were a big thing.

尽管现在看来这似乎也没有什么，但由于在当时电灯产业正刚刚起步，因此任何能够辐射光的材料都是被重点关注的对象。

By the end of the nineteenth century scientists had discovered that the amount of electromagnetic radiation released by an object changed depending on its temperature and they had measured these changes. But no one knew why it happened.

到了19世纪末，科学家们已经意识到，一个物体辐射出电磁波的多少取决于它自身的温度，不同的温度会产生不同量的辐射。科学家们已经注意到这种关联，但没有人能够回答为何会是这样。

In 1900 Max Planck solved the problem. He discovered that the calculations could explain those changes but only if he assumed that the electromagnetic radiation was held in tiny discrete packets. Planck called these "quanta" the plural of "quantum".

1900年，德国物理学家马克斯·普朗克(Max Planck)解决了这个问题。他发现，通过计算可以解决这一问题，但前提是必须将电磁辐射视作是单独的“小份”构成的。普朗克将这种“小份”称作“量子”。

A few years later Einstein used this idea to explain another puzzling experiment.

数年后，爱因斯坦给予这一思想，再次成功地为另外一个棘手的实验现象给出解释。

棱镜将光线分解为不同波长的色光↑

Physicists had discovered that a chunk of metal becomes positively charged when it is bathed in visible or ultraviolet light. They called this the "photoelectric effect".

此前物理学家们注意到，用可见光或紫外光照射一块金属板，金属板会带上正电荷，他们将这种现象称作“光电效应”，但对于究竟为何会出现这种现象，物理学家们都感到困惑不已。

The explanation was that atoms in the metal were losing negatively-charged electrons. Apparently the light delivered enough energy to the metal to shake some of them loose.

爱因斯坦指出，这一现象背后的本质是金属板中的原子在这一过程中失去了带负电的电子。很显然，照射金属板的光为这些金属原子带来的足够的能量，让其中的一部分电子能够挣脱原子结构的束缚。

But the detail of what the electrons were doing was odd. They could be made to carry more energy simply by changing the colour of light. In particular the electrons released from a metal bathed in violet light carried more energy than electrons released by a metal bathed in red light.

然而，如果更加仔细地审视这些电子的行为，就会发现一些诡异的现象。科学家们发现，只需要改变照射光的颜色，我们就能轻松改变光携带的能量大小。尤其是，科学家们注意到，相比接受红光照射的金属板，接受紫光照射下的金属板释放出来的电子拥有更高的能量。

This doesn't make much sense if light is simply a wave.

既然如此，那么如果光仅仅是一种简单的波就难以解释了。

透过云层的阳光↑

You usually change the amount of energy in a wave by making it taller – think of the destructive power of a tall tsunami – rather than by making the wave itself longer or shorter.

一般来说，要想让某种波的能量更强，你需要使它变得“更高”——想象一下海啸冲向陆地时的画面——而不是让波本身变得更长或是更短。

By extension the best way to increase the energy that light transfers to the electrons should be by making the light waves taller: that is making the light brighter. Changing the wavelength and thus the colour shouldn't make as much of a difference.

由此推断，要想让照射金属板的光能够为金属板释放出的电子传递更多的能量，那就应当让光这种波更“高”，简单来说就是，增加光照的强度。而改变光的波长，也就是颜色，不应该会产生什么改变才对。

Einstein realised that the photoelectric effect was easier to understand by thinking of light in terms of Planck's quanta.

在这一令人困惑的现象面前，爱因斯坦意识到，使用普朗克提出的光的“量子化”思想，能够很好地解决这一问题。

He suggested that light is carried in tiny quantum packets. Each quantum packs a discrete energy punch that relates to the wavelength: the shorter the wavelength the denser the energy punch. This would explain why violet light packets with a relatively short wavelength carried more energy than red light packets with a relatively longer one.

爱因斯坦提出，光是由许许多多微小的“能量单位”组成的。这种离散的能量单位与光的波长直接相关：波长越短，则其中的能量单位越密集。这样就能够解释为何波长较短的紫色光会比波长较长的红色光携带有更多的能量。

光让我们能够感受身边的世界↑

It also explained why simply increasing the brightness of the light made less of an impact.A brighter light source delivers more light packets to the metal but it doesn't change the amount of energy each light packet contains. Crudely speaking a single violet light packet could transfer more energy to a single electron than any number of red light packets.

它也可以解释为何单纯增加光照亮度并不会对金属板的电子释放产生什么影响——在更亮的光照条件下，光源的确会向金属板传输更多的“能量单位”，但并不会改变每一个“能量单位”内所包含的能量大小。通俗的说就是，单一一个紫色光“能量单位”能够为一个金属板中的电子传输更多的能量，而红色光的“能量单位”不管有多少数量，也达不到这样的目的。

Einstein called these energy packets photons and these are now recognised as a fundamental particle. Visible light is carried by photons and so are all the other kinds of electromagnetic radiation like X-rays microwaves and radio waves. In other words light is a particle.

爱因斯坦将这些“能量单位”称为“光子”。现在，光子已经被物理学界作为一种基本粒子予以承认。可见光是由光子构成的，其余所有的电磁波，包括X射线，微波和无线电波也都是一样。换句话说，光是粒子。

At this point physicists decided to end the debate over whether light behaved as a wave or a particle. Both models were so convincing that neither could be rejected.

到了这个阶段，物理学家们决定结束这场关于光是波还是粒子的旷日持久的争执——这两种模型都拥有确凿的实验证据，因此无法否定其中的任何一种。

To the confusion of many non-physicists the scientists decided that light behaved as both a wave and a particle at the same time. In other words light is a paradox.

让很多非物理学专业的人士感到困惑不已的是，物理学家们最终确认，实际上光辉同时表现出粒子与波的特性。换句话说，光具有波粒二象性。

Physicists though have no problem with light's split identity. If anything it makes light doubly useful. Today building on the work of luminaries – literally "light-givers" – like Maxwell and Einstein we are squeezing even more out of light.

但对于物理学家们而言，他们倒并不觉得光的这种双重身份带来了什么不便。相反，这让光变得更加有用。今天，在当年的先驱者们——如麦克斯韦和爱因斯坦等建立的基础之上，科学家们正在进一步探寻利用光的这些特殊性质的途径。

神秘的纠缠粒子↑

成对的纠缠粒子之间，任一成员粒子的状态发生改变都会立即引起另一个粒子的相应变化，这种影响不受时间与距离限制。

It turns out that the equations used to describe light-as-a-wave and light-as-a-particle work equally well but in some circumstances one is easier to use than the other. So physicists switch between them just as we use metres to describe our own height but switch to kilometres to describe a bicycle ride.

物理学家们逐渐意识到，尽管光的波动方程和粒子方程都能非常好的描述光的行为，但在某些特定的情况下，其中的一种描述方程会比另外一种更容易应用。因此物理学家们会根据不同情况在这两种描述方式之间进行选择切换，就像在生活中，同样是对长度的描述，但我们会用米来描述我们的身高，但会用公里来描述车的行程一样。

Some physicists are trying to use light to create encrypted channels of communication: for money transfers for instance. For them it makes sense to think of light as particles.

一些物理学家正在尝试利用光来实现加密通讯，比如用于安全的资金转账等等。对于他们来说，在开发这些功能时是把光看作了粒子。

This is because of another strange quirk of quantum physics. Two fundamental particles like a pair of photons can be "entangled". This means they share properties no matter how far apart they are from one another so they can be used to communicate information between two points on Earth.

这是由于量子物理学的另外一项奇异性质：两个基本粒子，如一对光子，其两者之间可以相互“纠缠”。这样的纠缠粒子之间存在一项令人惊异的性质：无论两者之间相距多远，它们之间都可以共享某些相同的性质，因此人们便可以利用这种性质来实现地球上不同两点之间的信息通讯。

Another feature of this entanglement is that the quantum state of the photons changes when they are read. That means if anyone tried to eavesdrop on a channel encrypted using the quantum properties of light they would in theory immediately betray their presence.

这种纠缠粒子的另外一项性质是，当对其进行观察时，将会改变纠缠粒子的量子态。因此，从理论上说，如果有任何人试图窥探使用了量子光学技术加密的信息时都将会立刻暴露。

Others like Goulielmakis are using light in electronics. For them it is far more useful to think of light as a series of waves that can be tamed and controlled.

而另外一些物理学家则更加关注光在电子学领域的应用。对于他们来说，将光视作是可以被操控的电磁波将会更有意义。

透过云层的光：它究竟是波还是粒子？↑

Modern devices called "light field synthesisers" can corral light waves into perfect synchrony with each other. As a result they create light pulses that are far more intense short-lived and directed than the light from an ordinary bulb.

一种被称为“光场合成器”(light field synthesisers)的现代设备可以非常精确的方式实现光波之间的同步性。这样它就可以产生相比普通灯泡发出的光线强度更高，持续时间更短并且具备方向性的光波脉冲。

Over the last 15 years these devices have been used to tame light to an extraordinary degree.

在过去的15年间，这样的设备被广泛用于对光的控制。

In 2004 Goulielmakis and his colleagues managed to produce incredibly short pulses of X-ray radiation. Each pulse lasted just 250 attoseconds or 250 quintillionths of a second.

在2004年，埃利弗舍瑞奥斯-古尔利马基斯和同事们成功创造出极短的X射线脉冲，每个脉冲的持续时间仅有250阿秒，一阿秒相当于100亿亿分之一秒(10的负18次方秒)。

Using these tiny pulses like a camera flash they managed to capture images of individual waves of visible light which oscillate rather slower. They literally took photos of light waves moving.

使用这种极短的光脉冲作为相机闪光源，研究组成功拍摄到可见光的单个波形图像，后者的震荡周期要比这种脉冲持续时间长得多。他们几乎拍摄到了光波在空间中运动的图像。

"We've known since Maxwell that light is an oscillating electromagnetic field but nobody dreamed we would be able to capture the light as it oscillates " says Goulielmakis.

古尔利马基斯表示：“我们从麦克斯韦的时代起就已经知道，光是一种震荡的电磁场，但在此之前还没有人能够想到，有朝一日我们甚至可以直接拍摄到真实的光波影像。”

Seeing those individual light waves is a first step towards controlling and sculpting them he says much as we already sculpt much longer electromagnetic waves like the radio waves that carry radio and television signals.

能够看到单独的光波是迈向控制和利用光波传输信息的第一步。目前我们已经利用波长更长的电磁波实现了信息传输，如我们利用无线电波传输广播和电视信号。

利用光的性质开发光学计算机，将大大提升未来计算机的性能↑

A century ago the photoelectric effect showed that visible light affects the electrons in a metal. Goulielmakis says it should be possible to precisely manipulate those electrons using visible light waves that have been shaped to interact with the metals in a carefully defined way. "We can control the light and through it we can control matter " he says.

大约一个世纪以前，光电效应向世人证明了可见光会对一块金属板内的电子产生影响。古尔利马基斯表示，未来我们将有希望对这些电子实现精确操控，方法是利用受控的可见光波，以一种精确的方式作用于金属板。他说：“我们能够控制光波，通过它，我们还将能够控制物质。”

That could revolutionise electronics leading to new generations of optical computers that are smaller and faster than those we have today. "It's about setting electrons in motion in ways we want creating electric currents inside solids using light instead of conventional electronics."

这一前景一旦成为现实，电子行业将迎来一场新的革命，从而导致新一代光学计算机的诞生，这类计算机将比今天我们所使用的计算机体积更小，运算速度也更快。古尔利马基斯表示：“要制造那样的计算机将需要控制电子，使其按照我们预想的方式运动，并利用光波控制电流在固体中的流动，而不是传统的电路方式。”

So there is one more way light can be described: light is a tool.

于是，我们对光又有了一种新的描述方式：光是一种工具。

That is nothing new. Life has been harnessing light ever since the first primitive organisms evolved light-sensitive tissues. Human eyes are photon detectors that use visible light to learn about the world around us.

这样的想法其实并不新鲜。自从地球上最早的生命诞生以来，生命就一直依赖阳光而获得能量。人类的眼睛是光子探测器，我们借助可见光了解我们身边的世界。

Modern technology is simply taking this idea even further. In 2014 the Nobel Prize in Chemistry was awarded to researchers who built a light microscope so powerful it was thought to be physically impossible. It turned out that with a bit of persuasion light would show us things we thought we would never see.

而现代技术只不过是让这个想法更向前进了一步。在2014年，诺贝尔化学奖授予了发明一种强大显微镜技术的研究人员，这种显微镜的能力强大到令人难以置信，甚至一度被认为在物理学上是不可能实现的。可以预见，随着技术的进步，光学还将带领我们目睹更多前所未见的奇景。

原文：BBC/Colin Barras