Slashdot Mirror
Negative Index of Refraction Created
FortKnox writes "Scientists studying how a new composite material reacts with microwaves have found that the waves refract in a way the defies a law of physics. The physical formula states that the wave will refract a specific way, but passing through this new material, the wave bends in the exact opposite direction. Scientists believe this is the first demonstration of a negative index of refraction." I haven't been able to find a more scientific report about this - if you find a link, please post the link below.
Sure you can. Just use light with a negative wavelength.
Second, people have been doing things sort of like this for a while, like the "left handed" materials.
Despite the fact that this is an overhyped piece of quasi-scientific nonsense, I still find it interesting. It provides us with yet more evidence of the failure of the open source movement.
Food placed in a microwave heat up beacuse of the change in elektromegnetic/electrostatic polarity of the oven. Water is a molcule with polarity(dipol), the oxygen end is a little bit more negativ then the hydrogen end. So a water molcule will start to flip back and forth creating the friction that heats up the food. (ty to heat somting dry...)
/Mikael Westerberg
sorry about the awful spelling.
mikael.westerberg@mbox332.swipnet.se
* No laws of physics are being broken. Negative (even imaginary) refraction coefficients are commonplace. What is new is the type of material being used, and the frequencies of light being refracted.
* It does not imply faster than light comms. Yes, light travels faster in such a material than it does in a vacuum, but that's only the phase velocity. The group velocity is unchanged, it it is the group velocity that counts in comms.
* It will not help create a wormhole or any such nonsense.
* It does not change Maxwell's laws in any way. Snell's law stays the same. The RHR and the RHL stay the same also.
* The material does not need to be less dense than air. Indices of refraction have nothing to do with density.
* IT IS NOTHING NEW!! People have known about negative indices for yonks! Read Feynman's lectures, he talks about this phenomenon, and he gave the lectures in 19 fucking 62!
See... http://www.aip.org/enews/physnews/2000/split/pnu47 6-1.htm
Bill - aka taniwha
--
Bill - aka taniwha
--
Leave others their otherness. -- Aratak
For my chaotic friend,
What was crap? you don't even say.
Whats wrong with the world today?
Incenced and idiotic punks
who posted before they thunk.
They can only vageuly point
at everything being out of joint
When they themselves have no proof
come off as arrogant and aloof
~^~~^~^^~~^
The right hand rule is not really a rule, it is a easy way to remember the direction of the positive cross product of two verticies. Its the same as putting your hands in front of your face to see which one forms an 'L' for 'Left' hand.
So tell me how these materials form a negative cross product of radiation across the E and M flow?
And what does this have to do with refraction?
No links to anything. You should be...
..proud of yourself. Fooled the moderators again.
~^~~^~^^~~^
This is what I was thinking to. I might be missing something here but isn't this almost certainly going to happen in the case where you have a substance through which microaves travels faster than they do through the atmosphere?
sigs are a waste of space
that's not quite it. that would simply give a less than 1.0 IOR.
I wonder if POVRay will let me simulate a negative IOR? I wonder what that looks like? Time to whip out the gratuitous checkerboard floor!
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
The paper by Shelby et al. is here, but I belive full access requires a subscription. (Most universities have this.) Wiltshire has a less technical Perspective in the same issue.
Bob
With negative index of refraction you are able to recreate the source field at some other "image" position. That means no resolution limits set by the wavelength of the light and and focusing power (usually called numerical aperture) set by the lens. Note that the negative refraction lens conjugates the phase of the wave. For a plane wave, it just looks like the wave reverses direction at the other side of the (flat) lens. For a spherical wave originating at some point, the conjugated wave will focus onto a point on the other side of the (negative refraction) lens.
For antenna research this will probably mean really a lot. Most probably we will also be able to locate sources of (microwave) radiation with great precision.
/jarek
--
"Convictions are more dangerous enemies of truth than lies."
There are two types of equations in physics. There are fundamental equations and derived equations. Fundamental equations are purely empirical beasties, whose sole justification for their existance is that they match the data that science produces when you plug numbers into them. In theory there are only two equations that are properly empirical, the general theory of relativity and the standard model of physics (in practice there are a few more physical phenomena whose underpinnings are not well enough understood to be linked to those two equations).
Then there are derived equations, like the special theory of relativity and the various laws concerning the index of refraction. These equations have certain conditions and assumptions built into them and it is possible to come up with phenomena that seemingly defy them because you're breaking the assumptions they're founded on. A nail sticking to a magnet defies the law of gravity, but that's only because the law of gravity by itself assumes no other forces in action, for example.
So in short no laws of physics were broken by this. No doubt some aspects of quantum mechanics were used to undermine what is effectively classical physics.
The scientists did NOT violate the laws of physics.
<p>
They found a substance in which low energy wavelengths will travel faster than the speed of light in air. This is different than the speed of light in a vacuum, which is a constant and would really screw things up if discovered false.
Ah. I must have been using wet ants.
"Reactionaries must be deprived of the right to voice their opinions; only the people have that right." - Mao
(These 1930's physics books are loads of fun.)
"Reactionaries must be deprived of the right to voice their opinions; only the people have that right." - Mao
Thbbbt.
If they're not going to make the next Furby or Tickle-Me Elmo with what they discover, why should they keep getting research grants?
"Reactionaries must be deprived of the right to voice their opinions; only the people have that right." - Mao
As for previous articles on this, IEEE Spectrum ran a story on this in January. If you have an IEEE account (or know someone who does) then you can see it here. This is a short "news in brief" style of article, but it still does a reasonable job of explaining the effect. The thrust of the article was actually about the potential use of this effect in semiconductor lithography (used for printing ICs).
Spectrum also references the original paper on this effect, which appeared in Physical Review Letters last October. This paper was written by John Pendry from the Blackett Laboratory at Imperial College, London, UK. His work was preceded by David Smith and Sheldon Schultz at the University of California when they built some of this so-called left-handed material using a "metamaterial". In fact, the theoretical background for left-handed material has been around since 1968 when the Russian physicist Victor Veselago first looked at it.
So this material has been around for a little while now. You just have to know the right places to look. :-)
Me and my lab partner came up with a negative index of refraction in a Physics lab in college. It was at that point that I realized that I should change my major from Physics to Computer Science.
Software sucks. Open Source sucks less.
The short answer is "yes". The long is "yes, if they can make it work at near visible wavelengths, since that's what most photoresist is designed to react with".
Theoretically, perfect lensing utilizing materials with negative indeces of refraction would allow resolution at near nanometer scales using visible or ultraviolet light. Obviously, the cost savings for fabs would be enormous. It's too bad most of the comments here thus far have overlooked this.
That's not to say there aren't other things to overcome before we make circuits on those dimensions. But it's a potentially important development.
Kythe
(Remove "x"'s from
Kythe
Um, yeah, what the other guy said. Scroll around in here and you'll find links to Nature (which is eminently more respectable than Scientific American), and that article notes that the research will be published in Physical Review Letters, which is a pretty damn solid place. I mean, it hasn't been independently duplicated yet, but it has gotten coverage in the "real" scientific press- Nature is not about to go spouting off unless they feel it is pretty solid. Those with mod points should feel free to mod the parent down.
~luge
IAAL,BIANLY
Wow, thanks for that information. Are you an idiot? Did you read any of the information posted in the links provided with this article? No, of course not. You just spouted crap.
In future, you might want to keep your mouth shut. It'll save everyone hassle.
This isn't really against the laws of physics of course :) Basically if you've ever done any electromagnetism then you'll have heard of the right-hand rule which governs the interactions of the electric and magnetic fields and the directions of their wave velocities. But for this new class of composite materials we instead get a left-hand rule, meaning that Snell's law (which governs the change of angel caused by the change of velocity of EM radiation through materials) is essentially reversed...
The really unusual thing about these materials is that they exhibit negative electric permittivity and negative magnetic permeability, never seen before in any material. There are sure to be plenty of interesting applications to follow.
The refractive index is directly related to the speed of the EM waves in the material.
When the waves bend the other way, then the refractive index is less than one. The speed of the EM waves then is: C / r . where, C is the speed of light, and "r" is the refractive index.
With r < 1, You get faster-than-light transmission. This violates some pretty basic physics laws.
I'm not sure what negative r and speed would imply exactly.
Roger.
Probably because as you said the metal was on the bottom? This should get it grounded to the oven so there are no visible sparks since no static charge can build up. Depends on how conducting the base of your microwave is, I guess.
Nice troll, pal. Are you really trying to say birds will fall out of the sky if we for some reason decided that a few of our physical theories were wrong?
Go you big red fire engine!
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
OK Mr. Cochrain, April Fool's Day is over.
If tits were wings it'd be flying around.
Actually, that's backwards. Making perfect spheres and parabolas is hugely easier than making an optical flat. There's a reason why amateur scope makers usually will grind their own primary mirror, but buy a secondary.
If tits were wings it'd be flying around.
Fiberglass and copper, eh? Well, how about the fiberglass REFRACTING it in the PROPER direction, and right after the copper REFLECTS it exactly the other way????
--
Yep! There was no such thing as electromagnetic waves until
ethernet was invented, because you need ethernet
for them to travel through.
Hamsters are at least as feathery as penguins. HamLix
There are about six thousand different things in physics that would have to be changed if the speed of light in a vacuum is not the true limit. This is true even if you just find some weird material that transmits it only slightly faster.
Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
ok, i'll bite.
isn't comparing the objectively observable behaviours of nature (minus the heisenberg principle) a far cry from observing the behaviours of mammals with very unique personalities?
observing one person's personality does not necessarily lend you insight into the next person's, and the same can be said for groups. the same thing goes with "physical" phenomenon. both diciplines require good analytical skills to find the relationships.
once you find things that appear to be static in nature, you can begin to find relationships with much more objective a set of experiments than you could with examining human behavious, but in both cases you can draw conclusions eventually (but, again, humans are just a bit more unpredictable to most observers).
this, imho, is exactly why studying human behaviour is both infuriating and intensely amazing all at the same time... ususally because it's so baffling. (take, for example, the mass phychology of the typical stock market)
i don't think either type of observation is really ever a waste (given that the data isn't destroyed)...
Peter
i should quickly add to this, i in no way condone the pork-barrel slop that occurs in common governments... i just wanted to try to defend folks that do "odd" experiments. sometimes they really do have worth :)
Ok let try this, this is what causes big analysis problems in geophysical surveys, if it don't refract, you can't see the layer. Basically, if the wave through the material is faster, then you don't get a signal back...
humm, someone post this on april 1?
Whomever rated this Informative obviously didn't read the whole post...
Your right to not believe: Americans United for Separation of Church and
I understand your sentiments, but don't forget that the laser was sat around in research labs for a decade or so before anyone thought of a use for it.
Now, I personally own two (one in my CD-ROM drive, one in my audio CD player).
As DeadInSpace said, don't knock it just because it doesn't appear to be useful now. You never know what we might think to do with it in the future.
Cheers,
Tim
It's official. Most of you are morons.
Are you saying you've gotten pulled over because the officer noticed red shift? That's pretty damn fast.
Photos of bits of the past hiding in the present: afiler.com
I think your reasoning might be backwards. I suspect the reason that amateur scope makers grind their own mirrors (starting from spherical), is because it's mucho cheaper than purchasing parabolics.
They're doing the hard stuff themselves, because they can't afford the huge bucks to get them pre-made.
IMHO.
********* sig: If you don't like the law, get filthy stinking rich, and buy a better one.
Looks pretty much like a flat sheet would cause divergent rays to be straightened toward parallel. That would be quite useful, since it's loads easier to make something perfectly flat than perfectly curved
********* sig: If you don't like the law, get filthy stinking rich, and buy a better one.
can be found at Science Magazine.
The article was published in today's issues of the journal Science, abstract. (A paid subscription is required to read the full article...)
Light also refracts when going (for example) out of glass back into vacuum. So it does indeed accelerate back up to full speed once it leaves the glass. There's nothing mysterious about going faster than lightspeed - different materials have different lightspeeds. You just can't travel faster than the speed of light in a vacuum.
--Ben
(Here in California we've got much smaller molecules.)
--Ben
Actually, if I remember correctly, microwaves operate by causing water molecules to vibrate, and have nothing to do with the size of the object being irradiated.
0x0D 0x0A
The correct answer is that microwaves cause a transition in the rotational energy level of water. Don't believe me? Prove it to yourself: Take a cup of water, and an ice cube. Make sure the ice does not have condensation on it (i.e. it is dry, not partially melted). Put both in the microwave at the same time. The water will boil well before the ice will melt. That's because ice does not have a rotational degree of freedom-the water molecules can't rotate when they are frozen, hence they cannot absorb the microwaves.
gosh, i'll bet that they never thought of that! maybe they never went through first year physics.
/. mods will mod up any post that uses the words "crystal lattice structure".
it's funny how
anyway, if it were less dense than air, the freakin thing would float. i think it would probably occur to them to check out the "lattice structure" when they found the sample floating near the ceiling.
Actually this is new (or rather, was new last year), since the index of refraction is the sqrt of the product of dielectric constant and the permeability. If only one of them is negative, you have an imaginary index of refraction, and no travelling waves, which is why AM radio is reflected by the ionosphere...
Good point! I obviously wasn't thinking much about what I was writing. :) However, the sqrt actually has two roots, a negative and a positive one, and when doing these materials one has to be very careful, since one is the correct root and the other is wrong.
It turns out that (solving Maxwell's equations) for negative epsilon and mu, the correct (as in most physically meaningful) index of refraction is negative. I have a friend who's worked on this kind of stuff, and it's very confusing, with the phase velocity and group velocity end up pointing in opposite directions. Very weird stuff.
8^) Not red shift, but blue shift. And yes, that's how radar speed guns work.
--
"You've crossed my Line of Death!" "What? No! Where is it?" "Here in the fine print...."
A paper recently published in Physical Review Letters outlines how it is possible to make optics that are not diffraction limited using negative index of refraction materials. If this material were made into a lens of the appropriate shape, it would be possible to resolve features much smaller than diffraction limit.
The minimum angular separation of two sources that can be distinguished by a telescope depends on the wavelength of the light being observed and the diameter of the telescope. This angle is called the diffraction limit.
One reason that telescopes must be made huge is that the the diffraction limit decreases with wider telescopes.
Optics made using a negative index of refraction do not experience the diffraction limit. A telescope only need be made large enough to capture sufficient signal.
This is old news.
>Old age and treachery almost always overcome youth and skill.
yes, but they die of old age shortly afterwards, which is just fine with the young and skillful
sean
For the refractive index to be negative, doesn't that mean that the speed of light through this medium has to be *higher* than through a vacuum?
I'm confused..
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
No, fats are made of fat (lipid molecules) -- think grease and oils. No water in 'em. Nothing magical about water -- it's just that there's water in just about any kind of food you put in a microwave, and water reacts pretty strongly.
--
+1 Insightful, -1 Troll. What can I say, I'm an Insightful Troll.
setenv DISCLAIMER=I_didn't_read_the_article
IIRC, index of refraction is the ratio of the speed of light in the medium to the speed of light in vacuo. Now, "speed" is the magnitude of velocity, and hence is always positive, so I don't know how the index of refraction could, by definition, be negative. It's as if the light
would not only slow down, but reverse direction (if they considered negative speeds to be speed in the direction antiparallel to the original velocity vector maybe?). In any event, I believe superluminal speeds would imply an index of refraction greater than 1, not less than zero, so I don't see any violations of special relativity here.
The UCSD physicists said they expect their discovery to open up a new subdiscipline within physics and produce an array of commercial applications for this material, on which the university has applied for a patent.
Hmm?
The university has (presumably) applied for the patent on the material, not on the subdiscipline of physics. As such, it seems a perfectly reasonable thing to patent -- they've spent a lot of money synthesising a complex new material, and now they'd like to make some money out of it... (and maybe use the money to fund new research)
--
Repton.
Repton.
They say that only an experienced wizard can do the tengu shuffle.
to my mind you cannot ever break the laws of physics...only your ideas of what the laws of physics are can be wrong.
Quidquid latine dictum sit, altum viditur
Hell, /. needs a LaTeX parser so that these math equations are more readable!
1 - wp^2 / w^2
I have no idea what this formula means, I just want it to look good. Even Figlets would be better than this.Later...
KangarooBox - We make IT simple!
What are the implications of this technology for satelite dishes? Can they be made smaller, cheaper, or am I trying to find a use for this technology way too early?
-bugg
Index of refraction is not a function of density - there is a correlation between the two, in that denser objects do tend to have higher indices of refraction, but that doesn't mean you can measure one based on the other.
My understanding is that a negative index of refraction is a property of materials that would result not from the light speeding up, per se, but instead by a wave traveling in the opposite direction and modifying the properties of the original wave - one of the results of a negative index of refraction is that the Doppler Effect will be reversed.
IANAKAR (I am not a kitchen appliance repairman) From my limited knowledge of microwave ovens, the reason that food heats up is because of friction between the microwave particles and the food molecules, which is why stuff doesn't brown in a microwave...
Or I could be talking totally out of my ring piece - but this is just a moo point.
--
Consultancy: If you're not part of the solution, there's money to be made in prolonging the problem
I know it's hard to read the article, when it's slightly more than one page, but it mentions that a negative index of refraction could give you a tighter focus than positive IoR values could give.
-Ted
Sigh. At least get it right. It's "two wrongs don't make a right, but three lefts do."
bzzzzzt! Try again.
Cooking microwaves run at a frequency of 2.45 GHz, which is a wavelength of 12cm. Water molecules are significantly smaller than 12cm. ;-)
There are a number of rotational and (to a lesser extent) vibrational water transitions around 2.45 GHz which get smeared into a band in liquid water. The molecules absorb the microwaves to get into excited rotational states, and then collisionally de-excite during collisions with other molecules, thus distributing the energy into kinetic energy of the entire food.
[TMB]
Initially when I read this story I thought (momemtarily forgetting the ACTUAL laws of physics):
"Hold on, wouldn't the refractive index of the material be between 0 and 1?"
The theory being that objects with an index above 1 "focus" electromagnetic waves while ones with an index below 1 would diffract them (same shaped object, btw).
This would mean though, that the speed of electromegntic waves in this material would be faster than light in air / a vacuum. this is just blatantly wrong as far a current knowledge dictates.
Now if this substance has a negative refractive index, there exists a 'hole' in the range of refractive indices from -1 to 1.
There is a possibility that the atoms in this material are placed so that the microwaves are reflected off some of the copper - resulting in diffraction. A substance that is transparent to a portion of the electromangetic spectrum does not interact with the radiation as it passes through. Although, a perfectly transparent substance is virtually impossible to find.
A couple of brief comments:
- You are right that AM is reflected by the ionosphere as a consequence of the negative dielectric constant. FM is not reflected because the carrier frequency is higher than the ionosphere's plasma frequency (giving a positive dielectric constant for FM).
- By the n = c_vac/sqrt(eps*mu) definition you mentioned, if both eps and mu are negative, the index of refraction is still positive. Perhaps the article meant to say 0 n 1 (still interesting; for example, laser-solenoid fusion is a wacky idea needing n1). Or possibly the researchers are using a more generalized definition of n. (General press is not the best place to get scientific details or scientifically accurate terms.)
- Having both eps and mu 0 has other stranger consequences (which is why such materials seem new and strange). The two interesting ones I can think of it that the material is left-handed and the material exhibits an inverted Cherenkov effect.
- Negative dielectric constants by themselves do not preclude wave propagation. Standard plane wave propagation in bulk negative dielectric media is out but many kinds of waves are possible at the material interfaces or via magnetic effects. Whistlers (the whistle sound you can hear on an AM radio) are an example of such wave in the ionosphere. (Whistlers start out as a lightning strike in the Southern hemisphere.) Schumann resonances of the ionosphere are another example.
- The article linked to did not specifically state that negative magnetic permeabilities had been created but similar research which made a couple of headlines last year did the same trick using arrays of split ring resonantors and other such microwave voodoo. As far as I can tell, this is the either same thing or a recent extension. In any case, devices like TWTs and backwards wave oscillators and what not rely heavily on creating devices which do similar strange things to wave propagation in them.
Kevin
Why does Slashdot keeps eating my less-than signs.
1 - wp^2 / w^2
In English:
One minus the quantity of the plasma frequency squared divded by the wave frequency squared.
I agree that HTML should support LaTeX or some other such equation typesetting convention. I know efforts exist but nothing is widely adopted. Until then, my emails and posts will use a bastardized quasi-LaTeX-ish equation markup.
Kevin
The stuff is interesting alright.
Opposite group and phase velocity is pretty easy to come by though. Think of the standard LC ladder with C as the shunt element. This turns into a standard transmission line in the limit of infinitesimal L and C.
Make the L the shunt element. Ta-da. Backwards waves (i.e. group velocity and phase velocity in opposite directions).
Kevin
Having just completed a Ph.D. in this field I can say with some certainty that negative indexes of refraction are not new.
The relative dielectric constant of a plasma (cold, unmagnitized, above the ion plasma frequency) is:
1 - wp^2 / w^2
where w is the frequency and wp is the plasma frequency. Below the electron plasma frequency, the dielectric constant of a plasma is negative. (Actually, part of my thesis addes terms to handle electron pressure and density gradient effects.)
Hell, Rayleigh (think 1900s) was using such treatments to calculate resonance frequencies for things like the sun (wp/sqrt(3) by the way).
What was somewhat new about the research referred to is they simultaneously created negative dielectric constant and a negative magnetic permeability.
However, the techniques they used to do so have been around since the 1950s and form the basis of all sorts of electron devices like traveling wave tubes (a staple of satellite communication).
Kevin
"Scientists studying how a new composite material reacts with microwaves have found that the waves refract in a way the defies a law of physics.
Somehow, I doubt it. The article headline says the same thing. The material doesn't defy anything, our knowledge of the laws is just lacking. It's a nitpick, but it's silly to say it defies the law.
The Good Reverend
I'm different, just like everybody else.
Heh, I was going to write a cutesy post about how the speed of light had been exceeded by three hundred times in a lab in New Jersey, then I find http://www.salon.com/people/feature/2000/08/03/lig ht/index.html, a post on Salon.com about how the scientist's results had been misrepresented by the media.
On the other hand I did find this http://www.neci.nj.nec.com/homepages/lwan/demo.htm from the New Jersey lab.
Get off my virtual lawn, you damned virtual kids!
I saw this a few months ago in Popular Science.
The have rows of microscopic tubes and other structures. It just is made in a way so that it reflects microwaves in a pattern opposite of normal.
They're working on getting the components of it small enough to be used for visible light, with its smaller wavelengths.
Ewige Blumenkraft.
Is that air or vacuum? It's been a while since I've taken Physics so I don't remember whether refractive index is defined with respect to air or vacuum - i'd be surprised if it was the former.
What it seems to me is that they have discovered a material where the waves travel faster than the speed of light in vacuum (hence they refract the other way). That would be a quite interesting discovery if that was the case.
Mmmm.. Donuts
Does this mean that I can build my lightsaber know?
wait wait wait..... how come a glass of water heats up? specifically, what's the wavelength at 2.4 GHz? *calculates*
0.125 meters, or 12.5 cm.
I do believe that if you have a thimble-sized cup of water, smaller than 12.5cm, it WILL heat up in a microwave oven...
What gives?
-----
> These modern kids don't know the simple
:-)
> joy of saving four bytes of page-0 memory
> on a 6502 box.
Actually, I do
And, I would probably fall under the category of "modern kid".
So there!
-----
Does this mean that I won't be able to fry ants with a magnifying glass made out of this stuff?
-----
Just a detail here: as far as I understood this, the refraction index is not negative, it is smaller than 1 (0n1), so it has the opposite refraction effect as most materials.
Opus: the Swiss army knife of audio codec
Phase speed is the speed at which wavefronts move through the medium, and it isn't limited by the speed of light. A techie example of a phase speed is the speed at which text scrolls across a rolling LED sign (we've all seen them). You can make the text scroll as fast as you like, in principle, because individual LEDs don't have to communicate with one another -- they just turn on and off at set times. You can even make the text scroll faster than light!
Um, no, you can't. If the signal to turn on a led has to get from one end of the device to the other, that signal can't travel faster than c. Electrical impulses are also limited by this.
If you're thinking, 'well, lets just put the signal generators at both sides' that won't get you anywhere, because you still have to synchronize the two, which will be off by a factor depending on the length of electrical path. Either way you cut it, I don't think you can do it.
Using your sig line to advertise for friends is lame.
If your measurements contradict the laws of physics, more than likely it is your measurement, your math, or the tools you are using to measure with that is wrong, not the laws of physics.
Gallileo may have been right. Newton may have been right. Einstein even have been right. But please, double check your math before you pretend to know more than the sum total of human knowledge.
Quite possibly they would;
If indeed we are living in a "Matrix" as depicted by the popular movie of the same name, we all only "believe" what we see; If for some reason, the "SYSOP" of the "Matrix" happened to change his "COMPUTER RULES" everytime we revised our "PHYSICS THEORIES" birds would fall from the sky.
For example, in the margin of this comment, I have proof that the speed of light DOES NOT remain constant in all situations;
i.e., The Road Runner and Wile E. Coyote are running away from each other at the speed of c/2 (each); However, the Road Runner, gets a little "turbo-boost" from eating his "SPINACH" and starts travelling a little bit faster, say "c/2 + 3"; Therefore I am right and the birds will fall from the sky.
Please proceed with this wonderful idea...
Utah's crown for "cold fusion capitol of the world" could move to Hawaii!
When I die, please cast my ashes upon Bill Gates -- for once, make him clean up after me!
we found a medium which slows the passage of time itself? wouldn't that do the same thing? Take a lens and accelerate it, would this happen too? slow down? Ack, the stuff of sci-fi =)
This mind intentionally left blank.
The KKK a bunch of sheetheads? You decide!
Physicist John Pendry of London's Imperial College has said that a material with a "negative refraction" would make possible the construction of a lens capable of focusing light to limits not currently achievable.
Could this affect the power of todays lasers?
There would be plenty of effects from that, take laserweapons, laser-booster lightcraft technology, much "cooler" physics experiments in class etc. ect.
- Knut S.
May just be me being lame
It says that it refracts *microwaves* with a negative refraction. Not light.
Acually, it specifically says that it does *not* bend light...
/.Mattsson - My native language is not English, so please don't whine over linguistic errors. (That's lame anyway...)
The big deal is the difference between two different kinds of speeds of a wave. The wave's group speed is the speed at which the wave energy moves. What determines refractive index is the how a material influence waves' phase speed, an entirely different beast.
Phase speed is the speed at which wavefronts move through the medium, and it isn't limited by the speed of light. A techie example of a phase speed is the speed at which text scrolls across a rolling LED sign (we've all seen them). You can make the text scroll as fast as you like, in principle, because individual LEDs don't have to communicate with one another -- they just turn on and off at set times. You can even make the text scroll faster than light!
Phase speed and group speed are the same in nondispersive media (that is to say, when all wavelengths are propagating at the same speed). In air and vacuum and the like, that's approximately true. But in a dispersive medium, where propagation speed depends on wavelength, they differ. An example of dispersive wave propagation is the motion of ripples on the surface of water. If you throw a stone into water and watch the individual ripples move, each tiny ripple forms behind and overtakes the overall ring of ripples, growing to a large size in the middle and then shrinking again as it gets away from the pack. The tiny individual ripples are following the phase speed, but the energy only propagates across the water as fast as the overall ring of ripples.
How is this related to negative index of refraction? Most materials reduce the phase speed of light, and hence have a positive index of refraction. But spatially coherent structures can have the opposite effect and raise the phase speed above C. You see the effect in microwave waveguides (pipes for steering radio waves) and in radio scattering through of coherent arrays of antennae. You also get it, albeit with much shorter wavelengths, in crystallography -- most crystals have a negative index of refraction for X-rays, as the crystal planes form waveguides for the short wavelengths.
To be honest, from the Reuters writeup I don't know what the big deal is or why UCSD issued a press release at all. Clearly we're not getting the whole story.
There was an article on Economist a while back about how a material with negative refractive index may make a perfect lens, one which the diffraction limit is overcome, etc.
See my post for a link to an article as to how a material with negative refractive index may lead to making a "perfect lens"
Personally I want to use this to create a temporary wormhole at the bottom of the bar's tap. Now this would be a partial wormhole (perhaps by size or perhaps find some way to having it have a very low mass threshold) Basically the other end would be at the bottom of my mug (to prevent over foaming). Perhaps by creating several of these across the bar I could siphon off of many sources. I would have a literal bottomless mug. (unless they switched locations on the tap I suppose...). Man, that would be a great way to make a black and tan. On the other hand, why put the entrance point on a tap, just put it in the keg. That way I don't depend on both my activation of my end, and the barkeep filling (not really) some other customers brew up.
I seek not only to follow in the footsteps of the men of old, I seek the things they sought.
Could you coat a military vehicle in this material for EM invisibility?
sarchasm: The gulf between the author of sarcastic wit and the person who doesn't get it.
Actually the index of refraction is not directly related to density.
"there is no corroborating evidence elsewhere on the net (I tried, believe me). " Have you looked at the links posted in one of the comments to this /. article?
This Slashdot lameness filter is reeally bothering me due to "junk character post", so here is just a link to a more scientific article just search for "Sheldon Schultz" on it.
I tried to draw a picture of what the light path would look like, but the ASCII art set off the lameness filter. :-(>
Imagine a waist-high block made of a material with a negative IOR, and assume it's transparent (yes, opaque materials still have an IOR). You fire a laser from your hand at some point on the block in front of you. When the light refracts, it actually refracts back toward your feet, rather than the far side of the block.
What a reverse index of refraction means is that the substance they are refracting light through is simply less dense than air. There have been no laws of physics broken here. What this means is the substance for whatever reason is less dense than the surrounding air. Perhaps it is a result of some interesting crystal lattice structure where pockets are created which are virtually little vacumns. I would take a closer look at the actual structure and crystal topography of the substance before announcing to the world that you have broken all the Laws of Physics!
Nathaniel P. Wilkerson
Domain Names for $13
Nathaniel P. Wilkerson
www.haidacarver.com
Do you think light is limited to the three little bands you can detect with your eyes? (Or two if you're colorblind)
Visible light is electromagnetic radiation, same as x-rays, infrared, radio waves, and yes, microwaves. They could all be considered light.
The only noteworthy difference is the frequency. The fact that the experiments have not worked with visible light suggests attenuation at those frequencies. Not a fundamental difference.
You can never equivocate too much.
... but it takes a score 2 reply with a different subject for any moderator to realize it :-)
The evaluation of an action as 'practical' . . . depends on what it is that one wishes to practice.
That would be an interesting experiment in art class.
DanH
Cav Pilot's Reference Page
Cav Pilot's Reference Page
UNIX - Not just for Vestal Virgins anymore
This is such a troll, and a lame one at that.
Rate me on Picture-rate.com
"and dear god does this website suck now." -- CmdrTaco
I knew that this seemed awfully familiar.
"
on which the university has applied for a patent.
"
This is physics, the patent will cover the material in question.
If it was software, it would cover the concept of negative refractive index.
In the case of physics, other people are free to figure out how to make other materials with a negative refractive index, with one click - noone is allowed to figure out an alternate implementation.
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. (Einstein)
The velocity of light in a vacuum is fixed.
It may change it's energy / frequency but not it's velocity.
From the point of view of a stationary observer on the event horizon of a black hole all infalling light is blue shifted an infinite amount - serious suntan lotion required. From the point of view of an observer at infinity looking at a light source on the event horizon it's inifintely redshifted - the light has no energy.
However, it's still travelling at the speed of light in a vacuum in both cases.
You can bend space, you can warp time, you can't change the speed of light.
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. (Einstein)
Or red shift if you're travelling away from the officer who then radios his mate to pull you off.
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. (Einstein)
Aw christ, I'm sorry I got that ass backwards
n=c/v
While the poster may have been a bit confusing, he was not trolling.
I believe that the poster was refering to a violation in pairity. Pairity, which is like saying that you are in a right-handed or left-handed coordinate system, is conserved in Strong, E&M, and Gravitational interactions, but not in Weak interactions. (Pairity was once thought to always be conserved, and now some think that Pairity, charge, and time reversal are all conserved together)
Refraction has always been thought of as an EM process because light is an EM wave; and E&M forces have always been thought to conserve pairity. So under the previous posters assumption, either E&M does not conserve pairity or there are Weak interactions happening.
And just so you know, the pointing vector is calculated by taking E cross B. The pointing vector points in the direction that the wave propogates.
n the index of refraction is the speed of light in the medium v divided by the speed of light in vacuum c.
n between zero and one would mean that light is traveling faster in the medium than in vacuum.
A negative index doesn't really make since in the same way. I would assume that in this special case |n| is greater than one and that the reflection about the axis is caused by some optical effect not having to do with the speed of light.
Crap. My Letters sub just ran out a few months ago, and they've already deactivated my login.
-- Still waiting for the Nike endorsement
No. They've discovered a material where a wave entering it travels in the reverse direction when in the material than it entered or when it leaves.
You'd expect that that would mean that waves would get reflected but if you do the maths or think about the wave on the boundary of the material you find that that's not the case... anyway that's the best I can explain it in laymans terms.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Hmm. Either I had a login and I didn't know it(!) or they've just discovered that they'd left password protection off the page... anyway I can't access it anymore.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Check out the following link to a PDF file:
Physical Review Letters
Warning: probably don't bother if you haven't studied Maxwells equations... definitely don't bother if you haven't heard of Maxwell's equations!
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"cmstremi
;-)
>How will this help me pick up chicks?
It won't. They will have better binoculars and be able to see you coming from miles away. It should help them find me though
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"The negative refraction is not entirely new... It has already been done. To start off with, the refraction index can be described as the ratio of the speed of light to the speed of light through the material. Remember when those scientists managed to pulse light in a cesium chamber 310 times faster than "c"? In that chamber, the index of refraction was in fact negative allowing such a thing to happen.
Anyways the discovery of the negative refraction index (or positive depending on your sign convention) is not physics-law-breaking. Light travels at c in a vacumn where the index of refraction is 1; these negative refraction indexes are perfectly possible so light can travel faster than c in physics so no law has been broken.
http://www.afrlhorizons.com/Briefs/0001/SN9912.htm l
Pretty technical stuff but check it out.
"I think you know what I'm talkin' about, Mr. President; We're gonna kill us a mummy!" - Bruce Campbell as Elvis Presley
I'm not so sure about this claim, and find it interesting that there is no corroborating evidence elsewhere on the net (I tried, believe me). If this isn't "Cold Fusion II", then Sheldon Schultz has some explaining to do. Why is this not published in the Scientific American?
I suspect we will read about it in the paper tomorrow, and there will be an Entertainment Tonight feature on it later in the week. What ever happened to responsible journalism and scientific inquiry?
Hype alone will not change the laws of Physics. Although it is true that light will bend according to the refractive index, it is the angle itseld that determines the index of Refraction, if I recall correctly. Therefore, light will bend one way when going from air into glass, and another when going from air into a vacuum. So which way does light go here? If it goes from a vacuum into the medium in the same way it would go from air into a vacuum (or glass into air, i.e., from a higher to a lower medium), then, okay, you have something there. But why doesn't the article bother explaining the phenomena?
It reminds me of that article wherein they claimed that they found something that travels faster than the speed of light. I am still somewhat dubious on that, since it is only infomation that has passed out of that medium faster than a light beam would have traversed the medium, but not the initial pulse: that was absorbed, I believe.
Of course, I am just one guy. I could be wrong here. But not about the dearth of explanation...
SDMI: Finally! Music that won't rip or burn! Brought to you by the fine folks at RIAA.
Ok, I think someone already mentioned that if the real part of the index of refraction (n) is less than one than light goes faster than c. The speed of a single frequency is equal to c/n. This however is just the speed of a single frequency. If you send a pulse through you will find that dispersion will slow the pulse down meaning that the pulse will ALWAYS travel less than c (pulses are made of many frequencies -- the frequencies travel at different speeds this slows down the entire pulse.) So yes a single frequency can travel in material (many metals for example have indices less than one but the also have high imaginary parts of the index of refraction which means there is a high amount of absorption.) But you can never send information faster than c so this doesn't break any laws of physics. The article wasn't very technical so it is hard to say but I imagine that there is some non-linear effect that is causing the light to bend in a strange way. I'd have to read the original article to see what is going on.
Chip manufacturing technology will soon run up against the physical boundaries imposed by the wavelength of light. As you probably know, chips are printed through the magnification of short-wavelength (ultraviolet) light. The problem is that circuts are now almost the the width of the wavelength of ultraviolet. Chip manufacture will (before too long), run up against a brick wall. So, the question is, will this ability to focus radiation allow the development of an X-Ray magnifying glass? Shorter wavlengths=smaller circuts=faster chips. Ideas?
What exactly would "negative" refraction look like? This sounds like a very late April fool's.
kha0S and Dr. Zowie have provided the most correct explantion so far.
a )
NatePWIII is incorrect for what is being discussed here, these materials are not less dense than air.
Materials that we are talking about are left-handed and semi(?)-left-handed. True left-handed mediums have both a negative permittivity and permeability. There are other materials that are not truely left-handed, some ordinary metals such as copper and silver have negative permittivity (still +'ve permeability) at optical frequencies.
As kha0S said these mediums behave exactely opposite that of right-handed mediums (in the sense of vectors E,H,and B). But Snell's Law isn't reversed, it becomes complex and hence describes change in the phase of incident waves.
Snell's law :
sqrt(epsilon1)sin(theta)=sqrt(epsilon2)sin(thet
So if permittivity (epsilon)is -'ve the sqrt()'s make the relation complex, ie. a+jb. This implies that the materials affect the phase of an incident wave. This agrees with what Dr. Zowie said, as phase velocity is defined as:
v = sqrt(permittivity * permeability)^-1
I'm not sure what happen with a true left-handed material (reversed vector characteristics but no phase change?), but with semi-left-handed material you can see that the phase velocity becomes complex also.
I hope this clarifies what kha0S said somewhat or makes any sense at all. There are still many other thing going on in these materials. A more complete explanation lies in how evanescent waves, EM field component that die away exponentially within a wavelength of their source, interact with conducting electrons in the materials we are discusing.
If I'm wrong please correct me. If you want more information look up the following researchers:
Sheldon Schultz (UofCal, San Diego)
David Smith (UofCal, San Diego)
John Pendry (Imperial College, UK)
Victor Veselago (Russian Acadaemy of Science)
- remove the primate to mail
Check out the Vinny the Vampire comic strip
"It is a greater offense to steal men's labor, than their clothes"
That's what this article from CNN claims. They don't explain their logic for that very well, but at any rate they claim to have made something that does the opposite and increases the speed of light. Odd article, but interesting.
mmm...physics...
At least not in the way people mean when they talk about breaking them.
Physics - indeed science in general - is basically a collection of so-far not disproven hypotheses - which are based on observation, experimentation and logical (mathematical) deduction.
There are no immutable 'laws' - there are only hypothesis for which no exception has been found.
It's actually really important that scientists don't think in terms of 'laws' - because most major leaps forward occur due to someone 'breaking' then re-inventing one of these laws. Or put it another way - we come across these observations which don't fit the hypothesis so we have to ask 2 questions
1) are the observations correct?
2) is the hypothesis correct?
If we think in terms of unbreakable laws we'll throw out Question 2 at the beginning.
Fortunately most scientists don't talk in terms of laws - it's a popular science term.
Wow. I think I actually understand what you are getting to. My own studies in relativistic refractive gullibology indicate that there is a theoretical possibility that we will some day be able to wrap bundles of gullible moderators (+2, informative, indeed) into a negatively-curved Riemanian manifold shaped as a paper airplane and ship them all down that wormhole back to Planet Golgafrincham where they came from.
I've never had excited cheese before. Sounds interesting. But I have excited moderators to 60% of the speed of bad karma.
Um, if this event occured, how could it violate the laws of physics? Obviously, the laws are wrong if they can be violated...therefore, the laws are the problem, not the event. Just some nitpicking, Alex Magidow
Or, if the article is true, and there is a medium where light has a negative index of refraction when leaving a vacuum going into this medium, then we'll just have to re-vamp our idea of the maximum lightspeed. Speed of light in a vacuum might have been the old record-holder and this be the new record-holder. Still, the speed of light is the speed limit for the universe, it's just determining the medium where light travels the fastest that's the problem. Previously it was a vacuum, maybe now it's this composite material, or cesium gas. I think we just haven't found the "full speed" of light.
Steven
-- I have marked myself unwilling to moderate-- I don't have other accounts to artificially inflate the karma of
The article mentioned above can be found here.
http://www.stp-gateway.de/Archiv/archiv199-e.html This is an accurate description of what negative index of refraction is and why it would be useful.
--SuperBug
This is all very interesting... but how will it help Bill Clinton get laid? Focus on the important stuff people! FOCUS!
With Regards,
Phillip H. Blanton
i read about this in scientific american (or something like that) a few months back, i'm surprised alot of people are hearing about it now. in that article, there were mentions of using this material in satellites and other imaging machines for things that earlier had not been possible. so its kinda exciting, but i think it will only affect the areas that cost alot of money :-) i dont think that there are any mainstream uses for this stuff, but then again, i could be wrong.
How will this help me pick up chicks?
"Physicist John Pendry of London's Imperial College has said that a material with a ``negative refraction'' would make possible the construction of a lens capable of focusing light to limits not currently achievable."
In future please read the article before you troll. Thank You
Slashdot: Proof that a million monkeys at a million typewriters can create a masterpiece
But is refractive index not defined as the amount light bends going from a vaccuum into a medium?
Slashdot: Proof that a million monkeys at a million typewriters can create a masterpiece
Check out this post to see why I ignore your request.
Slashdot: Proof that a million monkeys at a million typewriters can create a masterpiece
Ok my physics is pretty rusty but I always thought that the reason for light bending between mediums was that the light slowed down going from the less dense medium to the denser medium. Does this mean that the light accelerates when it goes into this new substance and if so is the light then travelling faster than light?
Slashdot: Proof that a million monkeys at a million typewriters can create a masterpiece
"Yeah, the speed of light sucks."
-- John Carmack, Wired 4.08, p. 189
"And like that
Just to summarize, the material has both a negative dielectric and a negative permeability. Velocity (both group velocity and phase velocity) remains sub-luminal because it is the product of the two that determines the speed of propagation.
-JS
P.S. This isn't really news anymore; the link I posted is 13 months old.
Vanity of vanities, all is vanity...
One time, we were driving to a nearby mall. Two maps said that Bent Tree Drive made a sharp left curve. We're tooling along, looking for the sharp left curve so we know there's only two more miles to go.
Well wouldn't you know it? Bent Tree Drive has been under construction for a month. The sharp left curve is now a sharp right curve, followed by two sharp left curves.
There's an old saying: "Two wrongs don't make a right, but three rights make a left." It had nothing to do with this.
Anyway, it's a good thing I was behind the wheel paying attention. Had I been expecting the sharp left curve, I would have driven the Cruiser into a lake. Fortunately, I made the right followed by two lefts and we all got to the mall safely.
In my humble opinion, something similar has happened to these scientists. Perhaps the prism was under construction. Maybe they didn't see the tiny detour signs or maybe some kids snuck off with them in the middle of the night. You know in the Road Runner cartoons when Wile E. Coyote turns the sign around? I'll bet that's what happened here.
In fact, I understand the scientists also painted a tunnel on the side of a mountain and the microwaves went right into it. See? That's exactly what I'm talking about. If they're really smart, they'll watch out for the oncoming train. It would be a shame if the train hit them and squashed them flat against the front before they could collect their Nobel prize.
Got a full tank of hot grits and a penis bird in the glove box.
Ever checked out the Golden Fleece Awards? Lots of projects that have no use whatsoever, done under the rubric of "pure science", with your money. Typical example: funding a study of behavior and social relationships in a Peruvian brothel to the tune of $97,000.
What kind of things can you do with a negative index of refraction that you couldn't otherwise? I understand that it refracts the "wrong" way, but what does that mean for science and technology? The article only says that it can do cool new stuff, but never says exactly what. If anyone with any ideas on this would care to enlighten me, it would be greatly appreciated.
You forgot this one, complete with JPEGs, MPEGs, and phone numbers: http://orpheus.ucsd.edu/cmrr/lhmedia/
Most plasmas have negative index of refraction for radio frequency waves. The index of refraction only gives the ratio of the phase velocity relative to the speed of light, but informaion is transmitted at the group velocity, which can never be greater then the speed of light.
The only problem with the ants is that you will have to use a concave lens to make it work, so you couldn't make a magnifying glass with the same shape out of the material. Also, doesn't this mean it has a refraction index that is less than air, and not in fact, a negative refraction index? (i.e. the difference of ri's of air and the material is negative.)
This tastes like granma! By george, you're right! it DOES taste like granma! We'll take a box of it!
http://www.phys.warwick.ac.uk/theory/seminars/curr ent.html
This will take you to some abstracts, there's links for the relevant paper to more information.
It Is the Nature of Information to Transgress Artificial Boundaries
While here is the full research article in science magazine.
Both of these require a subscription, but you can read the abstract without paying.
I couldn't find anything directly about the microwave refractor, but a search for "negative index of refraction" turned up three short pieces on the basic physics: 1 2 3.
Note that these involve putting conductors into the near field of the emitter -- that means within a fraction of a wavelength of the light source or microwave antenna. But to me, that just makes the metal an added piece of the antenna, and one well known directional radio antenna uses an array of metal rods in the path of the emitted waves...
I don't know if the rings and fiberglass arrangement is just a variation of this.
In a related story scientists have renamed the formula, sllens' law.
Obscure physics jokes rarely go over well.
--Joey
c'mon, this is the stuff that makes the stealth fighter "invisible"
Old age and treachery almost always overcome youth and skill.
Here is site at UCSD which goes into detail about the "Experimental Verification of a Negative Index of Refraction". Also, here is UCSD's press release the Rueters article is probably based on.
Ummm you would think a negative index of refraction would be well, um REFLECTION?
----------------------------------------------
The best lack all conviction
While the worst are full of passionate intensity
{YEATS}
Theoretically, a negative index of refraction could be used to bend space time, and create a region oof negative energy strong enough to keep a wormhole open and allow us to traverse great distances in space and time. I have written a paper on this which appeared in the Quantum Mechanical Review some months ago, and I am very excited about it.
I am currently looking for funding to begin the first tentative steps of building a Faster Than Light warp drive. Of course, it will not be completed for some time, and will have some difficulties, but I have already, under laboratory conditions, excited a small lump of cheese to 60% light speed (I chose cheese because it is organic and therefore can show what would happen to the human body).
Hopefully, all Mankind will benefit from this discovery, and we can approach our destiny in the stars.
I want to touch the Godhead. As a physicist, I think it is possible with negative refractive indices.
It's one thing to have a great experiment and declare that it disproves the laws of physics. It's another thing entirely to say it with a straight face.
We see this all the time in astronomy, physics's younger cousin. Sometimes, you point your telescope at a distant spot in the sky and you see something you've never seen before. But upon closer inspection, you realize that some bird has crapped on your telescope.
That's what experiments like this are: crap on your telescope. But unlike the birds' crap, which was put there inadvertantly, these experiments are often conducted with premeditation and deliberation. They seek to undermine our worldviews and make us mistrust our histories and traditions.
It's far better not to question fundamental laws of physics. With astronomy, you can get away with it, because at the end of the day, it doesn't really matter whether the sun goes around the earth or whether the earth goes around the sun. But with physics, your every move could have dire consequences not just for our little corner of the universe but for all phenomena everywhere.
I know I certainly wouldn't want to be responsible for having our universe disappear in a puff of logic.
This is a bit like calling a cylindrical coil with its ends capped by disc conductors connecting to ends of the wire, "a cylindrical conductor which breaks the laws of electromagnetism by having too strong a magnetic field and one differently shaped and oriented".
This wasn't some freak effect in violation of current theory, but a device carefully designed according to current theory.
It's cooler than fresnel lenses (which could be considered to violate optics laws, if you ignore their small structure and treat them as flat plates), but not really more profound in its implications.
--
Preserve old classics: copy your collection onto all hard drives.
What would be really interesting is if they could create a material with refractive index (n) less than 1. I do not mean negative, but |n| 1 ie 0.6 All you need is a transparent diamagnetic material with a relative permitivity of 1! This would violate the laws of physics though, (which the actual discovery doesn't) becuase the light waves would be speeded up by the medium, rather than slowed down, so you break the light speed barrier, and the principle of conservation of energy all in one shot. So i call to the researchers to break down the barriers that physics imposes and create me such a material. All you need to do is make air diamagnetic
Sometimes, I have a negative index of erection, but that's only when it's tired from a prolonged session of "dick tennis"!
------ 1001001
Check out the official version of the story. http://www-physics.ucsd.edu/lhmedia/
They shoot microwave through a grid of metal and it gets bent the other way. Big whoop.
View the legit experiment there -> http://www-physics.ucsd.edu/lhmedia/
Firing microwaves through metallic grids often does that. So much hype, so few facts.