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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.
isn't the negative index of refraction called reflection?
The Open Sores revolution is an optical illusion. If you are an open sauce coder you should probably switch to .NET now while you can.
I guess it has a bit of life left in it, but with the article talking about 'single molecule' focal points. I geuss we are about to run into a little wall if these ever actually make it to market.
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 don't respond to Anonymous Cowards, and I Never Mod them UP.
Comments on this one are going nowhere, fast. What a dud of a story. I mean who really cares. WHO THE FUCK REALLY CARES ABOUT QUANTUM COMPUTING THROUGH A TELESCOPE OR WHATEVER the fuck this is about. sheeeet.
It seems like a negative idex of refraction would imply that light is moving faster than c through the material, but obviously this is crazy. 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.
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)
BSD is for people who love UNIX. Linux is for those who hate Microsoft.
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"
http://pcblues.com - Digits and Wood
Sounds like this technology could drastically improve implementing Quantum Cryptography. Imagine, long distance completely secure connections , that are provably unbreakable. Lets see Carnivore tackle that.
Thinking is good, I think.
Unnatural optics create precise photonic lens
By R. Colin Johnson
EE Times
August 27, 2002 (5:51 a.m. EST)
WEST LAFAYETTE, Ind. -- Optical experiments using arrays of nanowires are demonstrating that the concept of a negative refractive index could be realized in practical systems. The work, done at Purdue University, attempts to reproduce results similar to those shown last year at the University of California at San Diego using microwave radiation. A negative refractive index, which is not found in nature, would allow scientists to construct new types of microscopes with unprecedented resolution and could allow the creation of novel photonic devices.
Since the first demonstration of a negative refractive index material, research groups around the world have been pursuing photonic technologies that appear to break the laws of nature. "The race is on," said Vladimir Shalaev, a professor in Purdue's School of Electrical and Computer Engineering. "We think there are about 20 other labs around the world rushing to create the first working prototypes at visible and communications wavelengths. We hope to have a prototype by early next year."
Shalaev is assisted by Viktor Podolskiy, a postdoctoral fellow at Princeton University, and Andrey Sarychev, a senior research scientist at Purdue.
A transmission medium with a negative index of refractions would enable a flat planar lens to focus light to precisions that are smaller than the wavelength of the light itself. With tunable versions of such photonic materials now being rushed into prototypes by labs worldwide, it is conceivable that not only could a "perfect" lens be created but that known electron effects could be translated into photonic operations to create sensors that could detect a single molecule.
"Conventional lenses cannot focus light in an area smaller than the wavelength of the light, but with our nanomaterials you can focus light down much smaller than its own wavelength," said Shalaev. "These metallic nanostructures might even be able to detect a single molecule of a substance, which will never be possible for conventional optics."
All materials have two fundamental electromagnetic parameters: permeability and permittivity, which respectively measure the capacities of a medium to form magnetic and electrical fields. The values of those parameters produce the characteristic bending of a light beam when it travels from one medium into another. In addition, since both parameters are always positive in nature, the electric and magnetic vector field components are directed according to the "right-hand rule," which can be represented by pointing the index finger of the right hand in the direction of propagation. The thumb and middle finger are then oriented at right angles to the index finger, showing the field vector directions.
With the photonically engineered materials, everything is reversed: The field parameters are negative, and the field vectors are described by a corresponding "left-hand rule." In addition, the electromagnetic direction bends away from the normal to the interface between two media, rather than toward the normal, as in Snell's Law.
Perfect-lens recipe
In 1968, Russian theorist Victor Veselago predicted that composite metamaterials might be engineered to have negative permeability and permittivity. Such materials, Veselago theorized, would interact with their environment in exactly the opposite way from natural materials. Using mathematical models, Veselago predicted that such metamaterials would follow a "left-hand rule," which would reverse their effect on electromagnetic radiation. One intriguing prediction was that the left-hand rule would nevertheless allow a flat lens to focus light to a point.
Veselago's prediction that such perfect lenses could be made from metamaterials lay dormant until 2000, when John Pendry, a physicist at Imperial College in London, showed that certain metals could be engineered to respond to electric fields as though the field parameters were negative. Pendry demonstrated different configurations of metal that created a left-hand rule for magnetic fields. In 2001, researchers at Imperial College and Marconi Caswell (London) announced a magnetic resonance imaging system using a magnetic metamaterial based on Pendry's design.
Last year, physicist Richard Shelby's group at the University of California-San Diego demonstrated a left-handed composite metamaterial that exhibited a negative index of refraction for microwave EM. The simple arrangement consisted of a planar pattern of copper split-ring resonators (SRRs) and wires on a thin fiber glass circuit board. The SRRs and wires were arranged into a two-dimensional structure with a repeated 5-mm lattice, with the wires located on the opposite side of the circuit board from the SRRs.
Now Salaev's group is working to scale down Shelby's 5-mm pitch to 15 nanometers so that instead of microwaves, light at visible and communications wavelengths can take advantage of negative permeability and permittivity.
To simulate their nanoscale metamaterial, Salaev's group had to model the behavior of left-handed metamaterials at the nanoscale. To do that, they had to turn to the study of nanoscale metallic structures that produce electron configurations called surface plasmon polaritons (SPPs).
SPPs are a "higher-order" object since they are part light (photons) and part plasmon. To complicate matters, plasmons are themselves higher-order objects, composed of free electrons behaving as a wave across the surface of a metal.
Optical amplification
Three years ago, Thomas Ebbesen at the NEC Research Institute in New Jersey reported that some wavelengths of light could be transmitted by a nanoscale metal grid with an efficiency of greater than one. That implied that the photons were being accelerated, rather than retarded, by the metal grid. Even stranger was the fact that the grid spacing was smaller than the wavelength of the photons, which normally would have blocked out most of the radiation. Theory said that almost no light should go through a hole smaller than its own wavelength, but Ebbesen reasoned that resonant waveforms across the surface of the grid, called surface plasmons, were performing a type of optical amplification on the incident photons.
Surface plasmons are collective oscillations of electrons at the boundary between conductors and insulators. Plasmons, themselves a collection of electrons, then meld with photons to form a new order of object, called a surface plasmon polariton. SPPs produce a reverse effect to a photonic crystal: Whereas the crystals exclude light at special wavelengths (so-called optical "bandgap" materials), SPPs enhance transmission in certain bands, creating the negative refractive index effect.
Resonant SPPs on the metal surface accumulate electromagnetic energy, operating like an antenna when the grid pitch is close to the resonant wavelength of the light. Thus, by changing the pitch of the grid, the wavelength of enhanced transmission can be tuned to a desired wavelength of light. An optical "near field" is generated when localized SPPs are excited by light. The resonating SPPs enhance the transmission of specific light wavelengths by several orders of magnitude, according to Salaev's model.
Now all the researchers have to do is build it.
"In the simulations, we took metal wires and spheres about 10 nanometers thick -- about 100 atoms wide -- and they functioned like nano-antennas for certain wavelengths," said Shalaev.
Clouds and waves
The tiny wires, 10-nm thick and as long as the wavelength of light they are tuned to enhance, were arranged in pairs parallel to each other. When the resonant wavelength of light hit the wires, they resonated, transforming a cloud of electrons into a wave (plasmon), which enhanced the transmission of light in a "left-handed" manner.
The simulations used the discrete-dipole approximation to verify that the plasmon polariton modes in tiny parallel wires were dependent on the incident-light wavelength and the direction of propagation. Verification of the existence of localized plasmon modes and their strong local-field enhancement when fabricated into composites convinced the researchers that left-handed materials in the near-infrared and visible could be built.
"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.
Shalaev's group experimented with many different nano-antenna shapes, from spheres and wires to more complex geometric configurations based on repeated fractal-like patterns. Each metallic pattern was analyzed for its ability to enhance light using SPPs responding to selected incident wavelengths. The winning designs are now being fabricated into prototypes, due out by early 2003.
Nobody has given the least thought to what they are going to do with all this peculiar junk after it gets to the end of its useful life. Just dig a big hole like any good primate and throw it in, right?
Dr. Frankenstein lives on.
Hic iacet Arthurus, rex quondam rexque futurus.
Completely offtopic but go check out the RIAA website They've just been hacked.
This comment was generated by a Squadron of Ultra Ninjas
Check it: http://riaa.org
text below->
Piracy can be beneficial to the music industry
Adult Entertainment
Wynton Marsalis Brings videos to Young People Inside RIAA with Eric Cartman
Money Matters
Where can I find information on giant monkeys?
When will you offer free movies?
Are there subscription music services up and running?
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.
ok, so how long until Law Enforcement agencies decide that optical computation needs to be regulated because of the unbreakable nature of quantum cryptography? yay another clipper debacle
Hacked and slashdotted.
They're really taking a hit!
Didn't we have a story about how skeptical scientists were about these results.
:-P
I'm still waiting for the next big breakthrough in quantum computing, but this new optical technology will give way to some really fast stuff. Just imagine having a quantum computer cpu with optical connections to a solid-state hard drive. At least there is something to look forward to in computing nowadays.
A computer is a valuable tool, so use it and stop whining.
If they could build optical circuits with this stuff, could they replace my silly blue wire? Sure optical is here, but could this bring it to my house?
Hmmmm....
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.
Is it just me or does "surface plasmon polaritons" sound like somebody left the StarTrek technobabble generator on overnight?
Actually way kuel stuff, SciAm had an article at length about this a few months back, and it was an awesome read... one of the other cool effects of this technology is optical microscopes that are orders of magnitude higher in resolution... visual systems that will let people look at things in optical frequecies that were limited to electron microscopy in the past (means we can see things way up close, that are still alive and kicking... or nanoscopic...)
"The future's so bright you need shades..."
I'm sorry it's not > 90 deg., it's 0 deg.
I forgot the conventions of defining the angle of incidence/refraction during a braino.
How stable is all this going to be? I have to believe this is only working in vacuum conditions at the moment. I doubt it's going to be hitting the inside of anyone's computer in the near future. As the article says, the first applications will probably be high power microscopes. Not too much else seems feasible in the near term.
You can only be young once, but you can be immature forever.
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
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Any *normal* material has R.I. 1.
thanks to
KhaOS for the subject line.
Any *normal* material has R.I. < 1. Light travelling faster than 'c' implies R.I. > 1.
/. & forgot 'Plain Old Text' implies HTML.
err. I am new to
indx1*sin(a) = indx2*sin(b)
Where a is the angle of the incident ray, b is the angle of the refracted ray, indx1 is the optical density of the first medium and indx2 is the optical density of the second medium.
is given by sqrt(permittivity * permeability). If they're both negative, the negative signs cancel. I think what people are trying to say is that if the index of refraction drops below 1, then the speed of light will be faster than in a vacuum. Although this has been demonstrated in optical fibers in areas of anomalous dispersion , this article is not talking about that...
Gheesh. I thought we had enought problems recycling our old CRT's. I wonder what kind of issues these materials are gonna have if they make it mainstream?
I wonder what country we're gonna pollute this time. Oh! Bad American!
This signature is a waste of 42 characters
This is simply astounding, folks. If this were possible, computers would be so fast that there really wouldn't be a need to build a quantum computer.
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
Go Boilers!!!
Sorry, had to say it, its my alma mater
And yes! its off topic!
All you are creating in your example is a convex water lense contained in a glass block. Your example dosen't really work.
After reading Dianetics(by Lron the nut) I came to the
conclusion that all Scientologists have negative
refractivity. All you need to do is strap a really
new CLAM to a gurney and position his or
her body under the laser of any cd player.
After 10 minutes under the laser, all of the Body
Thetans will starting chiming in at a Tone +40.0.
Hopefully you remembered to put on your goggles because
the scientologist will start glowing like a lighning
bugs butt.
At this point you can start downloading ALL data into
the Body Thetans of this very willing scientologist. The
only problem is that the data does not remain stable
for more than a month. So you will need to repeat
the procedure every month, unless the CLAM gets
cleared, in which case ALL of your data will have
disappeared.
so it would be in your best interest to keep the young
budding scienos from CLEARing.
one example, the speed of light might be faster than in vacuum.
No, the speed of light in the medium need only be faster than the speed of light in the surrounding medium--e.g. air.
120 characters isn't enough to explain it.
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.
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-
What I find particularly absurd is the reliance on the existence of so-called "negative numbers." Puh-leez.
Banach-Tarski Overdrive
C'mon, moderators. Anyone who mentions FTL speeds regarding negative refractive index either didn't read the article or hasn't understood physics beyond a few college courses. This is hardcore solid-state optical physics and stands up to peer-reviewed scrutiny. Sheesh.
Stefan
The most important aspect is the ability to focus light to a point finer than it's wavelength. The article discusses using visible light to image individual molecules. Up until now the only way to do such a thing with visible light was with the near field effect.
Another interesting application would be telescopes. Maybe we won't have to wait
for the space interferometers to see all
the cool stuff out there.
Retard. of course it works, I've done similar things many times.
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.
Negative refraction could definitely alllow you to have at least some sort of invisibility. If not the ability to make anything disappear like with some sort of "cloaking device", you could make materials that are completely invisible. They would be constructed of this material with negative refraction along with some other material, like fused quartz or something, so that you would have a composite material with a total index of refraction of zero.
I have thought about this subject before, and I did some research about different materials. Just think of glass. The only reason that pure glass reflects anything is that it has a different index of refraction as the air or vacuum or water that contacts it. If you notice clear ice that is in water, it is almost invisible since the index of refraction of ice is very close to that of liquid water.
There are many applications of this type of material. Does anybody have any ideas of some applications for a zero-refraction material? Perfectly clear windows? Practical jokes?
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.
plasmonic nanomaterials
Heck, that even sounds cool.
Envy my 5 digit Slashdot User ID!
3D Volume Holographic Optical Storage NanoTechnology patented 5 years ago.
http://www.colossalstorage.net
Its amazing to see how the scientific community
makes revolutionary discoveries on known
patented technologies ??
03/2001 photonics.com article
Slashdot quality declines as the number of hot grits posts decreases. - Provolt's Law, Apr-09-2005
...then it's exactly what you need in order to make this work. [Stop- HAMR time.]
Sig broken, watch for
Quoth the intro: "we hope to directly manipulate light, guide it around corners with no losses"
Stupid scientists, always reinventing the wrong wheel. Rather than blow billion$ and years of research trying to make light turn corners, just get a fricking ruler and make those pathways straight! Do dragstrips run around in circles ? No, they're straight. Straight = fast. I don't care if my optical CPU core is 20 inches long and 2mm thick with a big protective slab of iron wrapped around it, as long as it puts out 20ghz of pixel-twaddling goodness.
-Billco, Fnarg.com
been reading the original negative index of refraction paper from 2000 the following preposterous claim may actually be true. 1) a lens (actually just a flat slab) of negative index of refraction n=-1 would perfectly focus an incident wave IN THE FAR FIELD more tightly than the diffraction limit of light (i.e. to much less than its wavelength). (note I said IN THE FAR FIELD, we all know about nearfield stuff) add to this the recent fabrication of negative index materials and it gets more interesting. first the easy to understand part: n=-1 slab acts a lot like a phase conjugate mirror, except instead of being a mirror it does not reflect the light but rather refocuses it downstream. THE KEY POINT: BUT as we also know they must obey a diffraction limit on how well they can refocus the beam Why cant they do better? well the diffraction limit comes from the fact that not all the fourier components are there. where did they go? well one place they went was the aperature cut off. But suppose we built the worlds largest perfect lens so that the aperature cut-off did not matter. We still could not focus light below the size of wavelength Why? Well there is one other place we lost fourier compontents. imagine the following you have a light source that is smaller than the wavelength of light (e.g. a molecule! or maybe a nearfield light source). what happens? well the small size means there are fourier terms that have k-vercots so large that for any given wavelength they cannot propagate. that is they are evenescant near field light that quickly dies away. the K-vectors that can propagate, the small ones, cant be refocused to an object as small as the source. Thus you supposedly cant ever refocus light in the farfield to smaller than a wavelength of light. But wait! those evanescent waves die exponentially so they do reach the far field, just they are really really weak. suppose you were to selectively amplify them up and then refocus the light with out phase conjugate mirror? well then you could focus light to smaller than a wavelength. Now here is where it gets REALLY SPOOKY!, if you do the math a negative one index of refraction does exactly that, it conjugates the phase and it AMPLIFIES ANY IMAGINARY K-VECTORS!!!!!!!!! that is it AMPLIFIES evenescent waves. But wait "CONSERVATION OF ENERGY YOU SCREAM !!!!". Nope! not a problem, because evanescent waves dont carry energy. "Baloney" you say. well okay, imagine an evenescent wave propagating, where does its energy go? is it absorbed by the air? put it in vacuum and it would still be evenascent. No the poynting vectors conspire to recouple the energy back to the source of the wave. THe author claims this means one can amplify these waves at no energy cost.
The claims of this news story were already disproven here: http://www.utexas.edu/research/cemd/nim/NIM1.html
In short:
K.L.M. (a physicist)
Is that an optical CPU core in your pocket, or are you just happy to see me?
My deviantArt site
The key word is tunable. Canon et al. could make some seriously cool lenses from this stuff.
Looks like Pink Floyd were waaaaaay ahead of their time. Check out:
m oo n.html
http://www.superseventies.com/ac19darksideofthe
A Negative reftactive index prism clearly demonstrated way back in the 70s.
-ve R.I. doesn't mean -ve velocity.
The angle is actually between -90deg and 0deg (or if you like it this way, 270deg & 360 deg).
It's like this:
\
_|
\ air
-------------
/ medium
|_
/
For those who don't know why, it's because ST shows use terminology like 'plasmonic' as buzzwords.
The only way the typical /.er can pick up a chick is with a forklift. -- AC