Professor Tony Ryan
As we've seen, there's little doubt that mobile phones have revolutionised our lives, but are they the end point of communication?
You've probably heard of 3G mobile phones, that you can watch videos and films on.
And this is one such phone, with a picture of a baby.

You see, we can have pictures like this on our current handsets, but we couldn't watch things that stream.
So now we need to explore the future of the communications technology.

You see, in silicon, we're approaching the limit.
Single polymer molecules define how wide we can write the tracks and maybe we need a more efficient way of processing and sending information.
And the answer to this is staring us in the face, it's light.

[Light fills the lecture theatre.]

You see, electricity isn't the fastest thing on the planet, light travels much more quickly, so why don't we use that instead?
If you wanted to phone George W. and say, can we talk about global warming or something, you'd use optics and under the ocean would be a cable like this, so this has rather than copper carrying the messages, it has these optical fibres.

[Close-up shot of optical fibres.] And these optical fibres are just like these.

When you make that phone call from your house, the first part of the message goes down copper and then at the exchange it's turned into light and it travels all the way to the USA, not as electrical pulses, but as light pulses and I'm going to show you how.

So here we have a wave guide and that's what the copper does, so here's your phone call as it goes down the cable.

... You can see it's a series of flashes - noughts and ones.
You see, on that journey ninety-nine per cent of the time is taken in the copper to go from your house to the exchange and less than one per cent of the time is taken in the optical cable going under the sea.

So how is it done?
Well Bipin's going to help me show you.
So all the messages and we showed you a red message, fire into the exchange, so they're all different colours and then they get mixed together and sent down the cable and they become white, because we've mixed all of the colours together. [Overhead screen shows 'white effect'.]

And then when we get to the other end, the colours are separated and they zoom under the sea at three hundred thousand kilometres a second and when they get there that light's converted back into electrical energy.
Thank you, Bipin.

And the same technology allows us to turn an image into electricity.
So here comes Jon with his digital camera for the ... picture, right.
[John takes picture of Tony standing in front of the jumbo mobile phone.]
So in there, in that optical train is a piece of electronics, a semi-conductor, that has pixels and those pixels convert the image into electrical signals.

Now we all know that light's a mixture of colours and each colour we perceive is a distinct wavelength, or frequency, a segment of the whole spectrum.

To carry the information around the world, the optical cables rely on light being split into more than just its basic seven colours.

Did you learn this at school? 'Richard of York gave battle in vain.' Yeah?
So that's for red, orange, yellow, green, blue, indigo, violet.

And they're the words we use to describe the colours, but if you have optics that are very good, you can break white light down into many, many more colours than that and that depends on their wave length.

So if we're going to move information around quickly on a phone network, why not apply the same principle when we build computers?
So if we do that, we need materials that'll allow us to manage the light in the same way that we made materials that'll allow us to manage electrons.

So if we're going to replace the silicon chip with a much faster optical chip, then we can literally process information at the speed of light, so there's a challenge in making materials that nature gets there first, every time.

[Tony holds up a frame with mounted blue butterfly.] So this beautiful butterfly appears to be blue.
Well actually we turn as we tilt the butterfly the colours start to change. It gets a deeper blue.
This butterfly's actually brown and it has a surface that's mottled such that it produces diffraction and you only see the blue.

So we need to be able to make materials that can control light and here's an example from Sheffield.

[Close-up shot of blue liquid in container.] So this is a brightly coloured liquid, right, you can see it's a liquid, because it's flowing and the colour comes from, not the fact that the molecules are coloured, but that it's manipulating the light.

So if we put a spoon of the liquid in the base here and squeeze down the top, we get something that's actually bright green.

Can you see the green colour?
That green colour came from that goopy looking liquid, because the liquid has layers in and those layers only reflect the green light.
You see, the future of communications technology is like this - managing light.
We could use this liquid to make tracks by printing, but this isn't the only technological breakthrough in mobile communications.

You see, when you got your mobile phone out and it had an LCD display, that's why the battery runs out, it consumes a lot of power and it consumes power in the back light, the thing that makes it - come on.

You see, what we need to do is use light emitting devices, light emitting diodes.
And we see them everywhere.
What they do is they convert electricity into pulses of light, just like this.

The first LED's were red, like this one and they were made from a compound of gallium and arsenic, called gallium arsenide.
Then came yellow LED's and eventually blue LED's and we need blue LED's and they're made from gallium nitride to make white and that's what held LED technology back.

When you mix the colours, red, blue and green, you can make white, just like we see in the middle of the screen now.

These LED's are much more efficient at transforming electricity into light than a bulb.

[Tony stands by set.] The future of displays and lighting is here. The power consumption's so low. Look over here at the set. Here is an array of LED's. There's lots of them and their power consumption, the amount of electricity needed to drive them is less than a bulb.

If we could convert every traffic light in the UK to work in an LED's we'd save enough electricity to power a large city and we'd have to put far less carbon dioxide into the atmosphere.

So LED's are the future, but really the future is LED's made from plastic, because it's cheap and disposable.
So these are actually light emitting polymers and they work in exactly the same way as the transistor.

So they emit light and the UK's a world leader in this technology and the roll-up TV is just around the corner. So what about things that take light and convert them into electricity?

[A large solar panel is carried into lecture theatre.] This solar panel is the current state of the art. And what this is, is a big LED running backwards, but you don't get that much power out of them and they're big and heavy, that's what it needs these two big lads!

Whereas, this device that's running this clock, this is a polymer LED.
It's made from plastic, so it's light.

And it's much, much better at converting the light into electricity.
If you're a cricket fan, you'll like this, if we could cover the area of Australia with photo voltaic cells with solar cells, then we could provide all of the world's energy needs, just from the sun.

And we'd never need to get beaten at cricket again! [Laughter.]

So - Annie's going to come on and put something into this oven.
You see, this phone has a digital camera inside.
It contains what's effectively a very complicated solar panel. It takes a light image and converts it into a stream of electrical noughts and ones.
The picture is made up of pixels and each of these pixels is a semi-conductor and they give out a different voltage depending on the light that hits them.

So, what we did earlier was we can transfer this digital image to make ourselves some mementos of this immensely successful lecture!

[Tony holds up T-shirt with picture taken earlier standing by jumbo mobile phone.] You see, I'm going to get a new T-shirt which has the picture we took earlier. And Annie's going to come and recover her mobile phone, which has had printed on it - yeah, the same picture. [Applause.]

Thanks Annie.
So these serve two purposes. Not only will they remind Annie and I of the lecture, but they also encapsulate all the things I've been talking about today.

To get this picture of me on this T-shirt and mobile phone cover, we've had to convert light into electrons and then those electrons into a binary code.

We've used that to make an image with dyes and then we've transferred those dyes onto this T-shirt and onto the phone back.
And they're transferred by diffusion, which is the way we made the tracks in the silicon trips and now your eyes are converting the light you receive from this image into electricity and your brain says 'he's holding up a T-shirt.'
Thank you.

[Applause/music/credits roll.]