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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.
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.
~^~~^~^^~~^
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
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
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.
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????
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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.
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.
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."
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
Does this mean that I won't be able to fry ants with a magnifying glass made out of this stuff?
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Heh, just what I get for shootin from the hip. I described materials with positive but sub-1 index of refraction. This stuff has negative index and is really new.
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!"Check out the Vinny the Vampire comic strip
"It is a greater offense to steal men's labor, than their clothes"
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.
An anti-rainbow? That would be an interesting experiment in art class.
It would interesting, except to be an "experiment", you'd have to get an art class to follow the Scientific Method, including formulating a hypothesis, falsifiability, etc.
Ummm. Yeah. Cough.
How will this help me pick up chicks?
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
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.
When something strange is discovered (something previously often considered impossible), does it really matter if there isn't a use for it this very moment?
No.
If every discovery with no apparant use was treated the way you react, portable computers running at 1,000,000,000 Hz weighing less than 3kg would not exist today, just to name something. What if no-one ever tried to research and understand radio-activity (which would not seem very useful at the time), would we have the ability to take X-rays today? Or to try and cure cancer with it?
Scientific discoveries will almost always be of significant use, and should be treated as such. Even when there doesn't seem to be an application yet.
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