Thu
Sep 26 2013 2:45pm
MIT and Harvard Just Made a Real Lightsaber. So That’s Done.

real lightsabers photonic molecules Harvard-MIT

Cross another dream off the bucket list, because the Harvard-MIT Center for Ultracold Atoms just created a new form of matter that could potentially be used to create real lightsabers. (They report no progress on The Hoverboard Initiative, however, and the clock is ticking...)

Scientists at the lab are reporting that they’ve successfully managed to get two photons to interact with each other and form a “photonic molecule” that acts as if it has mass but maintains the properties of light. Photons as a rule contain no mass and don’t interact with each other, which is why two beams of light pass right through each other. Lightsabers aside, the creation of a “photonic molecule” is actually a Pretty Big Deal.

The lab achieved the creation of the molecule by reducing a cloud of rubidium atoms to near absolute zero (0 degress Kelvin). Particles, atoms, and molecules do very weird things when brought to this low-energy state, allowing for such oddities as near-cessation of entropy, superconductivity, superfluidity, and condensates.

This temperature is achieved by a process called laser cooling, which means that anything that uses lasers is automatically cool, which can reduce the temperature of atoms to a billionth of a Kelvin. (Outer space is a relatively balmy 2.73 Kelvin in comparison.) The lab then passed two photons through the supercooled cloud of rubidium atoms. The energy of those photons excites the cloud of rubidium because the photon just pulled up into the driveway with grandpa and OMG the backseat is FULL of presents yay grandma’s here!, and slows the photons as their energy passes from atom to atom.

Where it gets really weird is when the two photons interact with the atoms at the same time, producing an effect known as a “Rydberg blockade.” This behavior means that the atoms get a little overwhelmed (like, emotionally) and can only interact with one of the photons at a time. This means that the photons have to essentially push and pull each other along as they travel through the cloud of atoms imparting their energy.

That means the photons are interacting with each other by using an atom as an intermediary, forming a structure that acts like a molecule but probably looks like a sandwich. A delicious sandwich made of light.

Photonic molecules could conceivably interact with each other, opening up the possibly of creating two beams of photonic molecules that would interact with each other. Figure out a way to make those beams stop when they’re about two feet long and you’ve got yourself a sword!

Maintaining this lightsaber presents its own difficulties, since the molecules have to be constructed in a supercooled vacuum, which is presently beyond the reach of handheld devices such as lightsabers. There’s also the matter of containing the photonic molecules within a shortened beam, which might require a containment field of some variety and/or a better understanding of the photonic molecules themselves.

And in the end, photonic molecule lightsabers just might not be as satisfying as the lightsabers we’re accustomed to. You could bash at things with it, but a beam made of these molecules wouldn’t cut anything. On the upside, there’d be no chance of accidentally cutting your limbs off, or doing that to anyone else.

It’s also far more safe than the other option we have for making lightsabers: trapping superheated plasma in beam form. Photonic molecules wouldn’t burn your face off just by being in proximity to them, so that’s a big upside.

real lightsabers photonic molecules Harvard-MIT

In terms of practical uses for photonic molecules, researchers aren’t really looking at lightsabers. More practically, the creation of photonic molecules might ease the way towards quantum computing, at which point we will all have to buy new phones.

But we were going to do that anyway, weren’t we? The future is here!


Chris Lough is the production manager of Tor.com and wants money made of photonic molecules so that whenever he took out his glowing money everyone would be all, “That guy’s something!” Then he would pay for his Orangina and leave, with a tip of his hat and a wry smile for all.

22 comments
Joseph Newton
1. crzydroid
So...no. They did not make a real lightsaber. That's not done.
sure
2. sure
Linkbait of the day.
Gerd K
3. Kah-thurak
The experiment was about photon pairs that show some sort of attraction to each other after passing through a very specific medium. Honestly I dont see how this relates to a "Light Saber". It is not like the photons stopped propagating. And we are talking about two photons here... you would need a few more than that to do anything usefull in a cutting application ;-)
sure
4. LastActonHero
this is nothing new - it was already achieved a long time ago, in a galaxy far, far away
sure
5. SharkBait
Nope, nice try tho...
sure
6. N. Eugene
"Figure out a way to make those beams stop when they’re about two feet long and you’ve got yourself a sword!"

That is some epic handwavery.
sure
7. Billymac
I am wondering since this makes light work like it has mass so a beam of light hitting another would do more than just pass through each other.
Could this maybe allow for things like 3d holograms? Normally to project anything you need the projected light to hit something (a screen or wall).
I am thinking if you had an X axis light saber projector and a Y axis, where the 2 beams intersected you could (??) get visible dot in 3d space?
Or something like that....
sure
8. billymac
Or if you could modify the technology to allow something like the Star Trek Holodech that would be cool.
Only problem is that everyone in the room would get melted...
Lisamarie LiGreci-Newton
9. Lisamarie
Oh man, way to get my hopes up...and then dash them!
Gerd K
10. Kah-thurak
@billymac
No, it would be espeacially useless for holography because you would not see anything. Even if there were more then two photons AND they could be kept in one place AND directed where you want them to go, you would still not be able to see them. Because the only way to "see" a photon is for it to hit your eye. And why would anyone "get melted"?
sure
12. Spim Shat
}}} Only problem is that everyone in the room would get melted...

Actually, considering the absolute zero element of this, they'd probably turn into a popsicle and shatter like one of those liquid nitrogen experiments, only more freezy.
sure
13. Gerry__Quinn
If I could reliably lure my enemies into a room full of super-cooled rubidium vapour, I could probably kill them without having a light sabre anyway!
sure
14. Darth Chocolate
A light saber isn't 2 feet long. It's more like 2.5 or 3 feet. It's less than 12 parsecs for sure...
sure
16. KDF_333
umm wait, after skimming past the science words( that must be some alien language) in the article i realize that they have not made a light saber. BOOOOOOOOOOOOOOOOOO FALSE HEADLINE!
sure
17. ClintACK
Extremely, extremely cool experiment.

But, laser surgery is *much* closer to being a working lightsaber than this is.
sure
18. JulianBR
Actually, it would probably be more practical to envisage this eventually being developed into a Star Trek universe holo-deck type system rather than a light saber (I am an equal fan of both universes - I am just responding in terms of a more practical application)
Steven Halter
19. stevenhalter
While the Nature article for this particular experiment is behind a paywall, here is a paper on the theory behind it by the same people:
dash.harvard.edu/bitstream/handle/1/8000895/1103.3700v1.pdf?sequence=1
Gerd K
20. Kah-thurak
@stevenhalter
Intersting. I didnt even realize I could only read the Nature article because I am accessing the net via a university server ;-)
Steven Halter
21. stevenhalter
@Kah-thurak:Yeah, outside of a university (or other organization subscription to Nature) it can be "rented" for $2.99 for 48 hours through the Readcube viewer or other increasingly costly means.

It looks like Lukin kind of opened the door to the light saber flood when he said:
"It's not an in-apt analogy to compare this to light sabers," Lukin added.
Unfortunately, that became the sound bite rather than the very interesting other potential uses (like quantum computing).
Gerd K
22. Kah-thurak
I do not really get why Lukin considers the analogy to the light saber "not in-apt" though. The reasons why Laser radiation is not usable in the way a light saber is "supposed" to work stay pretty much the same even if some photons can be "tied together"... I guess he just got over-exited with his own work ;-)
Steven Halter
23. stevenhalter
Very much so. I'm guessing he was desperately trying to find an analogy to explain to the reporter and came up with one that wasn't very accurate but at least got a lot of attention.
sure
24. Nolan Kasa
Everyone its a common misconseption that lightsaber blades are lazers. there actualy plasma as stated on the offical star wars website. and plasma is able to be contained by a magnetic feild just as lightsabers are said to work in the books.

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