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Negative Refractivity for Optical Computing
zero_offset writes "This article in EE Times details Purdue's efforts to create a material with negative refractivity. One of the important results would be the ability to create optical computers due to the effect's tendency to amplify and focus light at wavelengths larger than the thickness of the nanowires used in the transmission system. Purdue's School of Electrical and Computer Engineering's Vladimir Shalaev says, "Using these plasmonic nanomaterials, we hope to directly manipulate light, guide it around corners with no losses and basically do all the fundamental operations we do with electronic circuits today, but with photons instead." Nanowires, surface plasmon polaritons, optical computers, nanoscale metamaterials, unnatural refractivity -- what's not to like?" We did a story on the first material known to have a negative index of refraction last year.
what this means is that u can bend the light BEYOND the normal. it is NOT reflecting off the surface of the material, but rather entering the material and reversing direction within it. (iMHO)
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I must have been out of the negative refractivity thread of modern physics, but I love this word...
"They had free drinks that night. Trevor was absolutely PLASMONIC. I mean... shit, man! he almost had a negative refractive index. Lucky we got him in a taxi when we did"
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wouldn't that mean you would have to FORCE electrons through the material? that seems like a bad consequence.
BSD is for people who love UNIX. Linux is for those who hate Microsoft.
It doesn't mean the velocity is faster than 'c'. It only means the light beam is deflected towards the opposite direction ( angle of refraction > 90 deg )
the ways one can escape these limits in a semantic sense is that you can change the index of refration of the media so the wavelength is shorter than in vaccum, but that's not really accomnlishing the goal. Alternatively, near field or or ther diffraction effects can confine a light field to a region smaller the wavelength, but it cant propagate in vacuum/air that way.
likewise the claim you could make a perfecly flat focusing lens by combining poistive and negative materials is pretty hilarious too. You can do that right now with conventional positive only materials. (example take two plano confave lenses of high index material, and fill the space between them with water. voila!).
on the other hand you could do a lot of really interesting stuff with negative index materials that is harder to put in laymans terms. one example, the speed of light might be faster than in vacuum.
Negative refractive index does not mean light is moving faster than C. According to Snell's law the refractive index of any material with respect to vacuum = velocity of light in vacuum / velocity of light in material.
So for dense thingies refractive index greater than 1. Eg glass. Now the refractive index of material A with respect to material B is Vel in B / Vel in A. So light travelling from Inside a glass slab to outside would think it encountered refractive index less than 1.
Now negative refractive index mean negative velocity ?? I dunno. Refractive index can also be calculated from Sine (incidence angle) / Sine (refracted angle). The only way to get negative refractive index is if Refracted angle greater than 180. (Remember high school trigonometry. Sine is negative only in the third and fourth quadrant). Now refracted angle greater than 180 would mean that light has suffered total internal reflection. So a negative refractive index material would behave like a mirror and not a lens. (hence giving negative velocity - velocity is a vector, has magnitude as well as direction). I smell a rat in the article.
-Dracken
Moore's Law describes an increase in transistor counts.
I hope you are referring to the idea that traditional microprocessor design would be obsolteted by 'optical computing' thus halting the advancement of traditional microelectronics, thus stopping the advancement of transistor counts as opposed to somehow having transistors being used in 'optical computing.'
Plasmonic nanomaterials
Plasmonic nanomaterials
Plasmonic nanomaterials
Now I'm sorry I went into software. I really, really wish I could tell people that I was into plasmonic nanomaterials.
Of course, with the computational power that will come of this, maybe we will be satisfied for a while. Somebody once said "Nobody will need more than 640 k of RAM" Right?
I'm not saying that more power wouldn't have many uses, but it always bothers me when people quote the "640K" line about modern computers. Imagine if Bill Gates, living in three bedroom house, had said "Nobody needs more than three bedrooms." And then now, living in a forty bedroom house, he says "Nobody needs more than forty bedrooms."
The latter, I think, rings a lot more true than the former. In most endeavors, diminishing returns can kick in after a while. It's the same reason we can't get away from the x86 architecture: There are more important issues than raw performance.
I thought the index of refraction was defined as:
n = (speed of light in vacuum)/(speed of light in medium),
or n = c/cmed
Now, convenctional wisdom and all modern science says c is always the bigger value, so n is always >= 1, but positive. How the heck does one get a negative refractivity? Niether of these quantities should be signed, let alone oppositely signed, right? What is meant by negative refractivity?
Tim
-- Hello_World.c: 17 Errors, 31 Warnings
Man, that's an awful lot of typos for someone in their 30's !
(vacuum, designs, stagnant, "whether or" "of it" obsolete)
And the people shall be oppressed, every one by another, and every one by his neighbour Isaiah 3:5
Ha! New words to play with. Let's see here...
;-)
'Surface plasmonic polaritrons...' Nah, too long. Let's condense it down to something like this...
"Give your laundry that FRESH, SPARKLING, NEGATIVE REFRACTIVE INDEX with Maytag's NEW SURFACE PLASMONITRON!! Yes, you too can have your clothes looking like they got lost in a physics lab for a month, AND REVERSE THEIR POLARITY, all in three easy cycles!!!"
(Read all warning labels before use. Not recommended for cashmere, poodle fur, or llama wool. Batteries most definitely NOT included, minor assembly and Ph.d required. This product is not available in Pakistan).
Ok... who else wants to contribute?
Bruce Lane, KC7GR,
Blue Feather Technologies
Is it faster? Cheaper? Less heat? More Compact? Some of these but not all of these? What do you lose by switching to photon?
It does sound like good stuff, but what exactly is the good?
There is nothing so silly as other peoples traditions, and nothing so sacred as our own.
um... it seems they're made of metal. So, shouldn't be any more nasty to the environment than, say, a few bottle caps. Not that bottle caps are good for the environment, but wouldn't it be more effective to ban, say, styrofoam than plasmonic materials?
I hereby place the above post in the public domain.
If they can fiddle with light and directly manipulate it, does this mean they could possibly simulate some form of "invisibility". E.g. bending light completely around an object, so that the object no longer refracts light itself, but is essentially hidden within a sphere of redirected light?
I suppose the current theory applies only to light within some conduit of sorts, like fibre optics, but it would be cool if it had other such uses
I'm not a physacists, so feel free to critisize, but it's just a thought... direct manipulation of light could be a powerful thing.
-Quote-
"Using these plasmonic nanomaterials, we hope to directly manipulate light, guide it around corners with no losses and basically do all the fundamental operations we do with electronic circuits today, but with photons instead," said Shalaev.
-EndQuote-
Stefan
Umm... what does this have to do with Quantum Cryptography?
now how would that work anyway... if you painted a basketball with "zero reflectivity" paint, you would no longer see the ball, because no light would bounce from it to your eyes, but you would also not be able to see anything behind it... so what would you see.. .or perceive??
Oh god, that woman is John Romero!
but in regards to the article, the final comment was sheer speculation. THe existence of a negative index suggests that it might be possible to create a composte substance with an index less than one yielding an electomagnetic propagation media with a speed faster than vacuum.
Today on slashdot, we have a nanomaterial that focuses light backwards, and also a nanomaterial that can attach to a flat, clean, dry surface well enough to support 200 lbs with a few square inches (using forces thought to only have effects at microscopic scales). The former is found only in labs and is brand new, and the latter is found in gardens and is older than humanity.
It's sort of interesting that the article refers to the negative refraction materials as "unnatural". Nature has been doing nanotech for millions of years now. It's pretty likely that, if these materials turn out to be good for anything that occurs in nature, they can be found there.
Computers are now fast enough to do the easy problems comfortably, even on quite large datasets. These are the ones people have in mind when they say computers are "fast enough."
But computers are no where near fast enough to solve large problems of the second kind, and it doesn't seem that they ever will be in the forseeable future. A problem of this type might be, "what lossless compression/decompression algorithm under 1000K in length has the highest average compression on a given sample dataset?" It's easy to write a program to solve this problem, but awfully hard to wait for it to finish.
I think we're falling into the gap between easy and hard problems. We can do easy problems easily, but have no feasible way to approach the hard problems.
plasmonic nanomaterials
Heck, that even sounds cool.
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