First Tunable Electromagnetic Gateway

[flyingcloud]

'Hidden Portal' Concept Described: First Tunable Electromagnetic Gateway

http://www.sciencedaily.com/releases/20 ... 083329.htm

ScienceDaily (Aug. 14, 2009) — While the researchers can't promise delivery to a parallel universe or a school for wizards, books like Pullman's Dark Materials and JK Rowling's Harry Potter are steps closer to reality now that researchers in China have created the first tunable electromagnetic gateway
The work is a further advance in the study of metamaterials, published in New Journal of Physics (co-owned by the Institute of Physics and German Physical Society).

In the research paper, the researchers from the Hong Kong University of Science and Technology and Fudan University in Shanghai describe the concept of a "a gateway that can block electromagnetic waves but that allows the passage of other entities" like a "'hidden portal' as mentioned in fictions."

The gateway, which is now much closer to reality, uses transformation optics and an amplified scattering effect from an arrangement of ferrite materials called single-crystal yttrium-iron-garnet that force light and other forms of electromagnetic radiation in complicated directions to create a hidden portal.

Previous attempts at an electromagnetic gateway were hindered by their narrow bandwidth, only capturing a small range of visible light or other forms of electromagnetic radiation. This new configuration of metamaterials however can be manipulated to have optimum permittivity and permeability – able to insulate the electromagnetic field that encounters it with an appropriate magnetic reaction.

Because of the arrangement's response to magnetic fields it also has the added advantage of being tunable and can therefore be switched on and off remotely.

Dr Huanyang Chen from the Physics Department at Hong Kong University of Science and Technology has commented, "In the frequency range in which the metamaterial possesses a negative refraction index, people standing outside the gateway would see something like a mirror. Whether it can block all visible light depends on whether one can make a metamaterial that has a negative refractive index from 300 to 800 nanometres."

Metamaterials, the area of physics research behind the possible creation of a real Harry Potter-style invisibility cloak, are exotic composite materials constructed at the atomic (rather than the usual chemical) level to produce materials with properties beyond those which appear naturally.

[flyingcloud]

looks a lot like black hole

[davesmith_au]

Tastes like dogshit to me too ... lucky we didn't step in it.

[flyingcloud]

I'd much rather have stepped in it, glad I didn't take a taste.

now the "portal", or "gateway" bit I don't buy

the diffusion of broad spectrum electromagnetic frequencies from a single physical locale is most intriguing
I would suppose that may resemble electromagnetic signatures currently observed beyond the "event horizion"
and possibly even accumulate visible distortions behind or beyond the "event" as an accretion disk, or fisheye

[junglelord]

Negitive refraction metamaterials or left handed materials are a real science.
The ability to create materials that posses qualities not found in nature is nanotechnology.
Metamaterials with a High K and variable (become negitive) permittivity and permeability based on charging rate are real technologies of the military. The nano structural qualities of these metamaterials and their specific resonante relationships to specific microwave freqs, for example, are areas of high investment and study. Tunable 2-d crystals offer a world of harry potter abilities. Like electrogravitics and stealth, No shit.

[Lloyd]

* Are portal and gateway the same thing? Are they supposed to be a way to transport living matter at the speed of light to a distant location intact, like on Star Trek or Stargate?
* Now see if the following on biophotons is relevant.
http://articles.mercola.com/sites/artic ... Light.aspx
* The existence of the biophoton field was scientifically proven by Dr. Fritz-Albert Popp in 1974.
* The DNA inside each cell in your body vibrates at a frequency of several billion hertz (which is unfortunately the same range at which modern cell phone communication systems also work). This vibration is created through the coil-like contraction and extension of your DNA -- which occurs several billion times per second -- and every time it contracts, it squeezes out one single biophoton; a light particle. That photon contains all the information on everything going on in your DNA at that moment. One single biophoton can carry more than four megabytes of information, and relays this information to other biophotons it crosses in the biophoton field outside your body. All the photons that are emitted from your body communicate with each other in this highly structured light field that surrounds your body.
* This light field also regulates the activity of your metabolic enzymes. This corresponds nicely with the findings in the study above that show your light field ebbs and flows along with your metabolic rhythm. The information transfer on biophotons is bidirectional, which means your DNA sends information out on a photon, and on the same photon the information of all the biophotons from your body is broadcast back to your cells, and to your tubulin, which are light conductive molecules in your connective tissue. The tubulin, in turn, receives the information-carrying light impulse and conducts it at the speed of light throughout your body, where it is translated inside each cell into activating or inactivating certain metabolic enzymes.
* Does anyone know or believe that the above is true? Are biophotons the same as ordinary photons? Is it possible for mere photons to hold 4 megabytes of info? If so, how? And, if that's possible, how many megabytes of info would be needed to tell how to construct a living creature? And then how many photons would be needed to be sent to a distant location and received and used to construct said living creature? Could photons be absorbed by rocks at a distant location and manipulate the atoms of the rocks somehow to form tools to construct creatures?

[mague]

Tastes like dogshit to me too ... lucky we didn't step in it.

Hahaha. Reminds me of the folk tales about creatures from hell. They are not allowed to enter your house unless you open the door and invite them.

Note to myself: Buy garlic

[davesmith_au]

When I read flyingcloud's response, I couldn't help but be reminded of Cheech and Chong...

[flyingcloud]

who is it?

Dave?

Dave's not here.

New Cloaking Method Could Shield Submarines From Sonar, Planes From Radar, Buildings From Earthquakes

http://www.sciencedaily.com/releases/20 ... 073508.htm

ScienceDaily (Aug. 17, 2009) — University of Utah mathematicians developed a new cloaking method, and it's unlikely to lead to invisibility cloaks like those used by Harry Potter or Romulan spaceships in "Star Trek." Instead, the new method someday might shield submarines from sonar, planes from radar, buildings from earthquakes, and oil rigs and coastal structures from tsunamis.
We have shown that it is numerically possible to cloak objects of any shape that lie outside the cloaking devices, not just from single-frequency waves, but from actual pulses generated by a multi-frequency source," says Graeme Milton, senior author of the research and a distinguished professor of mathematics at the University of Utah.

"It's a brand new method of cloaking," Milton adds. "It is two-dimensional, but we believe it can be extended easily to three dimensions, meaning real objects could be cloaked. It's called active cloaking, which means it uses devices that actively generate electromagnetic fields rather than being composed of 'metamaterials' [exotic metallic substances] that passively shield objects from passing electromagnetic waves."

Milton says his previous research involved "just cloaking clusters of small particles, but now we are able to cloak larger objects."

For example, radar microwaves have wavelengths of about four inches, so Milton says the study shows it is possible to use the method to cloak from radar something 10 times wider, or 40 inches. That raises hope for cloaking larger objects. So far, the largest object cloaked from microwaves in actual experiments was an inch-wide copper cylinder.

A study demonstrating the mathematical feasibility of the new cloaking technique – active, broadband, exterior cloaking – was published online today in the journal Optics Express. A related paper was published online Aug. 14 in Physical Review Letters.

Milton conducted the studies with Fernando Guevara Vasquez and Daniel Onofrei, both of whom are assistant professors-lecturers in mathematics. The research was funded by the National Science Foundation and the University of Utah.

Cloaking: From Science Fiction to Science

Cloaking involves making an object partly or completely invisible to incoming waves – sound waves, sea waves, and seismic waves, but usually electromagnetic waves such as visible light, microwaves, infrared light, radio and TV waves.

Cloaking things from visible light long has been a staple of science fiction, from invisible Romulan Bird of Prey warships in "Star Trek" to cloaking devices in books, games, films and shows like "Harry Potter," "Halo," "Predator," and "Stargate."

In recent years, scientists devised and tested various cloaking schemes. They acknowledge practical optical cloaking for invisibility is many years away. Experiments so far have been limited to certain wavelengths such as microwaves and infrared light, and every method tried so far has limitations.

Compared with passive cloaking by metamaterials, the new method – which involves generating waves to protect or cloak an object from other waves – can cloak from a broader band of wavelengths, Milton says.

"The problem with metamaterials is that their behavior depends strongly on the frequency you are trying to cloak from," he adds. "So it is difficult to obtain broadband cloaking. Maybe you'd be invisible to red light, but people would see you in blue light."

Most previous research used interior cloaking, where the cloaking device envelops the cloaked object. Milton says the new method "is the first active, exterior cloaking" technique: cloaking devices emit signals and sit outside the cloaked object.

Videos Simulate How Cloaking Method Works

The new studies are numerical and theoretical, and show how the cloaking method can work. "The research simulates on a computer what you should see in an experiment," Milton says. "We just do the math and hope other people do the experiments."

The Physical Review Letters study demonstrates the new cloaking method at a single frequency of electromagnetic waves, while the Optics Express paper demonstrates how it can work broadband, or at a wide range of frequencies.

In Optics Express, the mathematicians demonstrate that three cloaking devices together create a "quiet zone" so that "objects placed within this region are virtually invisible" to incoming waves. Guevara Vasquez created short videos of mathematical simulations showing a pulse of electromagnetic or sound waves rolling past an object:

In one video, with the kite-shaped object uncloaked, the wave clearly interacts with the object, creating expanding, circular ripples like when a rock is thrown in a pond.
In the second video, the object is surrounded by three point-like cloaking devices, each of which emits waves that only propagate a short distance. Those points and their emissions resemble purple sea urchins. As the passing waves roll by the cloaking devices, waves emitted by those devices interfere with the passing waves. As a result, the passing waves do not hit the cloaked object and there are no ripples.
Milton says the cloaking devices cause "destructive interference," which occurs when two pebbles are thrown in a pond. In places where wave crests meet, the waves add up and the crests are taller. Where troughs meet, the troughs are deeper. But where crests cross troughs, the water is still because they cancel each other out.

The principle, applied to sound waves, is "sort of like noise cancelation devices you get with headphones in airplanes if you travel first class," Milton says.

Protecting from Destructive Seismic and Tsunami Waves

"We proved mathematically that this method works when the wavelength of incoming electromagnetic radiation is large compared with the objects being cloaked, meaning it can cloak very small objects," Milton says. "It also can cloak larger objects."

Because visible light has tiny wavelengths, only microscopic objects could be made invisible by the new method.

"The cloaking device would have to generate fields that have very small wavelengths," Milton says. "It is very difficult to build antennas the size of light waves. We're so far from cloaking real-sized objects to visible light that it's incredible."

But imagine incoming waves as water waves, and envision breakwater cloaking devices that would generate waves to create a quiet zone that would protect oil rigs or specific coastal structures against incoming tsunami waves. Or imagine cloaking devices around buildings to generate vibrations to neutralize incoming seismic waves.

"Our method may have application to water waves, sound and microwaves [radar]," including shielding submarines and planes from sonar and radar, respectively, and protecting structures from seismic waves during earthquakes and water waves during tsunamis, Milton says. All those waves have wavelengths much larger than those of visible light, so the possible applications should be easier to develop.

"It would be wonderful if you could cloak buildings against earthquakes," Milton says. "That's on the borderline of what's possible."

The new method's main disadvantage "is that it appears you must know in advance everything about the incoming wave," including when the pulse begins, and the frequencies and amplitudes of the waves within the pulse, Milton says. That might require placement of numerous sensors to detect incoming seismic waves or tsunamis.

"Even though cloaking from light is probably impossible, it's a fascinating subject, and there is beautiful mathematics behind it," Milton says. "The whole area has exploded. So even if it's not going to result in a 'Harry Potter' cloak, it will have spinoffs in other directions," not only in protecting objects from waves of various sorts, but "for building new types of antennas, being able to see things on a molecular scale. It's sort of a renaissance in classical science, with new ideas popping up all the time."

A video showing an object uncloaked and cloaked as a wave passes may be seen and downloaded from http://vimeo.com/6092319 or as separate videos from http://vimeo.com/5406253 (no cloaking) and http://vimeo.com/5406236 (with cloaking).