Storing Light In Chips

Roland Piquepaille writes "Recently, researchers have "stopped light" by storing light pulses in hot or extremely cold gases (check these former stories on Slashdot or at BBC News Online). Now, scientists from Stanford University have devised a method to store light pulses under ordinary conditions. In Light-storing chip charted, Technology Research News says this opens the way for all-optical communications switches, quantum computers and quantum communications devices. The researchers plan to demonstrate this technique by trapping microwave signals within a year. They think that a prototype which works at optical frequencies could be made in two to five years. This overview contains more details and references."

Schrodinger

This was predicted by Schrodinger in the 30's - it really took them a long time to do it.

Re:Schrodinger

And to this date, nobody actually *tried* tying buttered toast to a cat's back, for the hovering-cat effect!

Re:Schrodinger

Maybe the toast would just force it's buttered side to the floor, squishing the cat.

Re:Schrodinger

Hey, it took centuries to get around to using Copernicus's orbital equations with spacecraft. This is the beauty of basic research. It eventually has a practical use, but you can't base its validity on how long it takes to use it. And you have to distinguish between research and the ability to invent something. As John W. Campbell once pointed out, the Classical Greeks had everything necessarily to invent the phonograph, though it wasn't until Edison that somebody got around to doing it. In that particular case, it was the mental rut into which the Greeks had worn themselves that kept them from making much practical progress, thus leading to the return to power of irrational religion and the eventual rise of the Dark Ages.

Re:Schrodinger

It isn't Copernicus' equations that are used for spacecraft, but Newton's F=ma, Newton's law of gravitation, and an occasional use of General Relativistic corrections.

Not hard

Storing microwaves within a year isn't very hard. I mean a year is huge!

Practicality in Displays

Anyone know if this would help out in display technologies?

Ie, instead of refreshing a CRT, if the light was held until it was no longer needed?

Might pave the way to some new display technologies =)

Re:Practicality in Displays

Well, if the light is held, it's not getting to your eyes, and thus not making a visible picture. So in that particular instance, I would think that this wouldn't help very much.

Re:Practicality in Displays

LCD's do that already! They stay in their state until they get a signal to change their brightness. They arent scanned like CRTS are! Thats why they look more clear/are thinner etc/.

That's wrong on a lot of levels: LCDs do not store light, they selectively block it. Liquid Crystals (that give LCDs their name) do not stay in a fixed state on their own, but must be regularly aligned. Small and old displays use scanning very similar to CRTs, modern and large displays have a memory cell for each pixel.

quantum?

quantum computers are still, and will be, a very very long way off. it is not enough to say that one single development will speed their coming, rather one obstacle will be replaced by another - sod's law

So far I've seen..

So far the comments have talked about using this for communcation / processing devices. Some have mentioned using this tech as weapons and such.

I'm wondering if light or other waves stored in such a fashion could be used as a battery of sorts.

Quantum Leaping?

When can we step back into the past and correct someone else's mistakes?

Please tell me how this time it's different.

Keep in mind that this is only theoretical. The researchers plan to demonstrate this technique by trapping microwave signals within a year. They think that a prototype which works at optical frequencies could be made in two to five years.

Does this sound like another one of those "breakthroughs" in optical/quantum computation where prototypes are "just around the corner" and commercialization is "just a few years away", yet it never happens?

Tell me how this time it's different. Does it work on standard fab processes?

I would really love a CPU with a terahertz clock. I guess it would still be I/O bound, though.

Re:Please tell me how this time it's different

Yeah I was excited reading the article until this quote.

"The work would have been more impressive had the authors demonstrated the stopping of light experimentally, he added." Raymond Chiao, a professor of physics at the University of California at Berkeley.

Yup one of those 2-5 years things again, like so much else...

Optical gets bypassed by other denser tech?

I wonder if optical will simply be bypassed by other, already denser technologies. Semiconductor feature sizes are an order of magnitude smaller than a wavelength of light -- giving them at least a 100-fold advantage (assuming the an optical computer could even have useful feature sizes at wavelength scales). Commerically available HD densities are over 100 bits per micron-square. And this does not even count on any new nanotechnologies in circuits or storage.

I'm sure that optical will have a role in the future. The ability to send ultrahigh bandwidth signals over long-distance fibers is extremely valuable. All-optical switching/routing would certainly improve latency. The ability of light beams to nondestructively pass through other light beams also makes it ideal for denser chip-to-chip and device-to-device interconnects. Finally, holographic memory storage migth have a future (although it would not surprise me if current HD densities are probably on par with expected future holographic information densities)

That's why I doubt that we will see an all-optical future. Other technologies already provide better densities in circuits and storage. Only in the realm of communications, does optical really shine.

Re:Optical gets bypassed by other denser tech?

Dude, check out my light harddrive.

..Opens case, goes blind and loses content of computer

Re:Optical gets bypassed by other denser tech?

I wonder if optical will simply be bypassed by other, already denser technologies.

There are two primary restrictions on current micro-processors. One is our ability to manufacture large deformity free wafers of silicon. The other is the excessive heat generated by the electricity. Both have been slated to slow our progress along Moores Law using conventional micro-processor technology.

What are the alternatives? It is possible to build deformity free cubes of silicon. However, in a 3-dimensional chip the heat generated (grows with the cube of the height of the chip) is dissapated through surface area (grows with the square of the height of the chip) so it compounds the second problem.

A probable alternative is the substitution of man-made diamond wafers for silicon. Diamond is far more heat-resistant than silicon, and can be created deformity free by plasma layering processes. Unfortunately the technology is still nacent and wafer sizes are still miniscule.

Optical computation would clearly provide a heat advantage. Imagine the newest supercomputer powered by a flashlight. But regardless, the greatest advantage of this technology, if realized and implemented for even a small set of basic algorithms, will be quantum computers.

Is it really storing light?

The article gives the impression that these chips are storing or freezing light. I dont see how this is possible. If they were truly "storing" light how would one know? The way I see it, is that if you can "see" or "observe" light then by definition the light must be escaping.

Re:Is it really storing light?

Yes, the concept (it is only a theoretical concept, not a chip, in the paper) does store the light. When the optical pulse is completely within the postulated structure (meaning only a very short pulse can be stored), a modulation of the refractive index causes the fields associated with the pulse to be stored in the internal cavities of the crystal. Reversing the refractive index change causes the stored fields to reform a traveling wave, which exits the structure. The way that you know that the pulse has been stored in the computer simulations is that after the first refractive index change, nothing comes out of the structure. After the second change, a pulse emerges that has the same shape as the one that was sent in.

Re:Is it really storing light?

Light is just energy. Think about when light passes through glass. Do you think it just stops on one side and then appears suddenly on the other side out of nowhere? The molecules in the glass store the energy of the light, then pass it onto the next molecule. Therefore for a very short amount of time that molecule stored the light. But what seems to have been done here, is that the scientists were able to keep the molecules in that excited state for a longer amount of time. BTW I did not RTFA, used to be a Phys Eng major.

Marketing

So soon the computer industry will see the same marketing as for soft drinks...

I can picture the billboards: Buy a computer with a Pentium Light(tm) inside

Another Step

Another step in the right direction. It seems more and more like optical processing is the way that computers are gong to go in the future. We all know that the current (no pun intended) electrical processors are not going to be sustainable. Primarily for heat, lithography, and quantum interactions on the traces.

This seems like a step in the right direction. I wonder if it can be used for memory or just buffers of a sort. Don't get me wrong, I don't think anyone expects a transition from electrical computers in the next decade, but the breakthroughs on the optical front seem to be accelerating.

Diamond transistors X Light-based networks

What I think about is the future ability to create custom and finely tuned diamonds with different amounts of "impurities" grown into it with .30nm amounts of detail.

What if you can not only use diamonds for electronic media, but also use the refractive nature of diamonds for storing and moving light?

Couldn't the different light "switches" and other networking technology be added into diamonds as they are grown?

Could you use something like that to grow 3 dimensional computer chips and storage media?

Also aren't diamonds pretty much destruction proof... could you were a future computer in a ring or a harddrive in a earing?

These chips should be named...

...The silmarils!

Speed of light?

IANA physicist, so I'm probably missing something here, but I thought that the speed of light [google.com] was actually a constant. Now, I did RTFA, and it states: The researchers' simulation shows that light pulses can be slowed to less than 10 centimeters per second. What's up?

Also, as for storing light temporarily -- has anyone considered using a "mirror trap", in which the light would bounce around until the trap was opened?

Re:Speed of light?

If you had just looked at some links in your Google search you would have found this:

To be precise, what we usually call the "speed of light" is really the speed of light in a vacuum (the absence of matter). In reality, the speed of light depends on the material that light moves through. Thus, for example, light moves slower in glass than in air, and in both cases the speed is less than in a vacuum. Link [utk.edu]

Mirror Trap?

No, here's what you need. You take a microwave transmitter and blast a second or so of bits at the moon. Wait three or four seconds, it echoes back. Receive it. Correct the errors (you did use error-correcting code, didn't you?), then send it to the moon again. And when it echoes back transmit it again. And so forth. First trick: you can correct and retransmit simultaneously with the reception. So you can have more data in flight than you have memory for on Earth. Second trick: you'll note that the power you get back is far less than what you sent out. But you can still retain the data. You have to act as a repeater, but that's all.

You could do this with mirrors, but the mirrors will probably be too close together to store very much. Still, a laser, and a nearly 90 degree angle, and the light will zig-zag a lot, and you might have a few hundred feet before you need a repeater. Damned dusty mirrors! Damned non-transparent air!

Third trick: with the moon, you now have a sort of bubble memory, but it's over 100,000 miles long. You could do the same trick with 100,000 miles of fiber-optic cable. But if you could slow down the speed of light you could use shorter cable (or store more in the same cable without having to drive the frequency and the bit rate really high). Also, you could shorten the period, which means your data is available sooner.

If you can really slow down light to a few cm per second, then you can store a lot of stuff. But you will need power for the repeating.

(What would be better is to make windows out of this stuff. You could look out the window and see what was happening outside yesterday. But imagine the solar power applications if you made the glass twelve hours thick instead of twenty-four. Sunlight would shine in during the daytime, and come pouring out at night!)

Not a big deal

My flashlight has been able to store light in it for quite a while now. Just because they can do it on a chip now isn't a big deal.

Awesome Windows

I always envisioned some sort of window that passes light VERY slowly. Basically you take this window, stick it somewhere like florida for a while (years whatever) then you put it in a window. You see the sunshine and awesome views of florida until it runs out. At which point you swap it out to get recharged. It would be expensive but for buisnesses or something in a rainy area like Oregon (where I live) for instance.

This is good news!

Hooray, after all these years of being told that chips are fattening someone has finally managed to make chips with light in!

Now if someone could just replace the sugar in Coke with light and I could eat my standard programmer's diet without getting fat enough to break my chair.

if only

If only they could make it capture the light from the goatse.cx guy before it reaches my eyes...

Have been doing this for years...

I have been storing light in my fridge for years. Even when it's dark outside and I check, it is still there...

Stargote Atlontis

Funny how they keep using that 'A' letter (the one with the ring on top, Slashdot seems to auto-convert it to a normal A?), which is spelled like 'O'... So when "Stargate" is spelled "Stargote", this new one, "Stargote Atlontis" sounds even more crazy. I hope the show itself will be good though, like the original Stargate... :)

Laser in a box?

I wonder if this might eventually be a way to get around the size and power limitations of lasers... You could create a burst of laser light using a big clunky machine, freeze it, then take the light pulse with you. If you had a bunch of these pulses stored in, say, cartridges, you'd essentially have a light, ultra-portable laser with little need for a power supply, albeit one that will produce a limited number of pulses.

Opens the way... AGAIN!

Technology Research News says this opens the way...

I know I've heard this spin several times before on optical processors, and just about every new advancement touts such claims. So I ask when WILL we see 'the way' as actually being "opened???"

Of course this reply opens the way for people to flame me silly. And that IS a fact!

Sorry to be Cynical

I'll believe it when I see it. I still have a cold-fusion reactor sitting on my desk; it was supposed to work in a beaker!

What's the big deal?

I've had my microwave in storage for over a year. What's the big deal?

Lights last longer in the freezer

Every time I open the freezer door, there is light.

Other light bulbs around the house seem to burn out all the time and my wife is always turning up the furnace - coincidence? I think not.

Do lights last longer in the north? What's the deal with those Northern Lights I hear about?

Photonic Battery?

An all-optical computer requires storing light with its wave state intact for signalling: either its envelope, waveform, spin states, or some other modulated state decodable as information. How about a material or device that merely stores the photons, as power? As we look at more efficient transmission of power derived from light (solar), or delivered as light (lamps or displays), the photon/electron conversion becomes a liability. It eats power, and constrains possibilities for the workings of the machine.

How about a photonic battery? I remember seeing AT&T research in 1990 desribing a 4bit optical benchtop computer that stored info in light along extremely long fiber spools, so a significant fraction of a second transpired as it cycled through its mirrored trap, allowing it to be read and written entirely in photonics. Is there a better material than traditional fiber for storing light in a small space? What is the actual power capacity of these fibers, anyway? Never underestimate the power capacity of a supertanker of equatorially solar charged optical bricks, especially if they contain more than 3.5E10 joules:m^3 (gasoline): 10E16 joules.

Re:Bright Chimps

When I read the first line in your comment, it looked like "Storing Light In ChipMunks" - I wondered what would happen when they were hibernating in Winter; would they glow or turn dark.