DARPA-Funded Device Adjusts the Speed of Light With the Twist of a Knob

so now the million dollar question. what can "slow light" or fast light for that matter, do?

I have a question to through out there, if you would be in a room,where no light can enter or come out of, you have a light emiting device set to extremely low light speeds (visibly lower, since i guess you wouldnt notice a difference of 1300 slower nor would you notice 100,000 slower or would you?), what would you see when you start to move? or say throught a fast ball? would time slow down or would you just be blind or would you see yourself where you were 5 seconds ago, or a elongated tube of yourself following your path but with no light coming from where you walked along that path? if you looked in a mirror?

One thing I'd like to have clarified is whether the light is slowed only within the chip (as I suspect) or even after it leaves the chip and travels through the room (which I find unlikely).

I had to make an account to respond to the comments above.

The speed of light, as far as we know, is constant. Nothing can either slow down, nor speed up, the actual speed of light. Slowing photons, as was done by the aforementioned researchers, is done by colliding them with electrons. Once the electron absorbs the photon, it gains energy and jumps to a different energy level. Since electrons would rather stay at the lowest possible energy, the photon will then be emitted, returning the electron to its original energy level.

This process takes time. A very short period of time, but slower than if the photon passed through unhindered.

should have asked your question first @SteveMcQuark lol but it was just cool to try and imagine. So to follow drinny26, how would it be applicable?

Siromar the speed of light is only constant in a vacuum, not everywhere.

@ tcolguin

Amen or Apeople

At above, why are there still spammers!!!

Light can be bent, slowed and consumed by large enough bodies of matter. We've observed this.

A female researcher even brought light to a visibly slow crawl with two lasers and a cloud of sodium I believe. Her reports stated that the light could be viewed as a slowly moving hologram of the information it's transmitting such as a picture of someone.

Even if this phenomenon is only restricted to the devices that make it possible, that leaves a lot of possibilities for information encryption, transmission and decryption.

Imagine quantum encrypted messages that are also protected by the precise speed at which the light is moving. A message that can only be read at particular speeds with at least 1200 levels to choose from is pretty awesome.

Or how about turning down the speed of information being transmitted over a circuit when a processor is undergoing heavy stress?

I imagine this can also be helpful in televisions and projectors. This might have applications in glasses-less 3D or 3D holographic projections in open space.

I'll be very interested to see how this gets applied.

Hopefully it helps push quantum computing a little closer...

@tcolguin, the speed is indeed only constant in a vacuum; for the reason I specified above. ;)

I am a little surprised that no one has mentioned why they might want this. For secure communication and/or code/key.

think about it. you send a single by laser, the enemy intercepts it but cant decoded it because they don't know what speed the laser is suppose to be decoded at. This is just one step in the process, but give this tech a few years to grow it could be implemented into any all all coded information.

Another use might be to shoot a huge blast of light towards enemies on a battlefield that illuminates the baddies. Follow the light with your rifle and shoot what you see as it moves through. Assuming you can slow it down more than a factor of 1200 because it'd still be going 500k+ mph.

"...could lead to a variety of applications in optical devices, communications, and computing." Such as...?

Once again, PopSci has failed to write an article that asks or answers the most basec questions. Sure, this is a super cool new technology, but WHY did DARPA ask for it and WHAT can we do with it?

It looks like this article got lots of people confused :-)
I recommend searching Wikipedia for "Slow light".

Looks lik the late Bob Shaw's "Light of Other Days" short story, written in the 1960's, is coming true!

It seems to me, if you can encrypt a signal using a specific speed of light, you should also be able to increase the data density. If (when) interaction between the speed of light and the frequency of light, if any, are accounted for, the information capacity could rise to an extent that is unimagined as yet.

Belive me...everything can be hacked or cracked :)

This needs to be stopped. This could potentially make a two hour episode of "America's Got Talent" last three weeks.

Phase modulation?

@inaka_rob, that's EXACTLY what I said...

@alias; the light doesn't continue to move slowly past the device. Light will always go its set speed for a particular medium - let it out of the controlled lab environment and it's back up to it's normal speed.

So think about this in DARPA terms. D=defense.. as in DoD funded projects. What would *you* as a military entity do if you could control the speed of light. If you could not only control the speed of light but combine that with your other DARPA funded projects of BENDING light around objects, and now you've got a perfect setup for a cloaking device that can adjust itself to any environment, in real-time, while its moving. In a few years and with a bit more development, this could lead to advanced cloaking technology.

As far as encryption goes, if you built a modulation device that changes the speed of light roughly 2k times a second while putting data packets out there through this beam of light, unless you had the exact same modulation device on the receiving end with the exactly same synchronization as the transmission device, you would never be able to break the encryption.

I would imagine it's some diamonds/CNT prism chip voodoo