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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.
~^~~^~^^~~^
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.
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
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 Vinny the Vampire comic strip
"It is a greater offense to steal men's labor, than their clothes"
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.