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Light stopped in crystal

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posted on Sep, 22 2005 @ 09:19 PM
A team of researchers from the Laser Physics Centre at the Australian National University in Canberra succeeded in setting the record for 'stopping' light, increasing the total time by a factor of 1,000, The light stopped for one second.

Dr. Matthew Sellars stated that the objective for 'stopping' light is to develop memory for quantum computing. He said:
“Stopping light is not just a neat trick, it is the basis of a quantum memory — a device capable of storing and recalling the quantum states of light."

Here's how its done:
“We use a small silicate crystal doped with a rare-earth element, praseodymium. It is on the praseodymium ions that we store the light pulse. “When we shine a laser pulse at this crystal, it’s normally absorbed. The light doesn’t get through the crystal. Then we add a second laser beam that turns on the coupling between the nuclear spins and the light. This coupling makes the crystal transparent. So when we now fire the first laser beam at it, it gets through, but the odd thing about it is that it takes a very long time to do so.”
“To store the light in there, we turn the second laser beam off. The signal from the first laser beam is trapped inside the crystal. To get the signal out again, we turn the coupling beam on again. We can now store light for seconds, and potentially quite a bit longer."
(Dr. Matthew Sellars, Laser Physics Centre, in PhysOrg)

The next goal is to stop and store a single photon, creating the first quantum memory.
"And this stopping light, what we're doing is transferring the quantum information which is on the light, or a complete description of the light field.
"We can now store it on the crystal and hold it there for a long time, for seconds and hopefully longer, and then come back basically just flick a switch, and then recall that quantum information and regenerate the light pulse. "It should be an exact copy of the pulse that we've put in. So rather than using electrons we'll be using photons, we'll be using light pulses to control our computer system."
(Dr. Sellars)

I found this quite intriguing, I'm glad to see there is a good amount of research going into research for quantum computer systems.

What are your opinions on this?


[edit on 9/22/2005 by iori_komei]

posted on Sep, 23 2005 @ 12:41 AM
I used to work with a physicist at the U of Maryland who was researching along these lines. Holographic light storage in crystals in hopes of creating a new data storage technique. Neat stuff, weird guy.

I look forward to hearing more as this technology advances.

posted on Sep, 23 2005 @ 03:54 AM
Well, actually this news is a bit on the older side, but still very exciting!

The first break-through came in 1999 when Dr Hau actually amazed the science community by slowing light down to 60 km/h (36 mph) by passing it through chilled sodium gas. And then in 2000, she reported slowing light down to 1.6 kph (one mile an hour) - slower than a slow walk.

In 2001 they could bring it to complete stop by cooling a gas of magnetically trapped sodium atoms to within a few millionths of a degree of absolute zero (-273 deg C).

(Source BBC News

The difference now is that they're using a (rare) crystal and there seem to be no cooling necessary.

They're saying it will be great for super fast computers, I say it'll open up a whole new world (figuratively speaking)... This is quantum physics... The possibilities... I can only guess. But I think Einstein is getting restless in his grave... Cool find!


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