Photon absorbing cloaking device

[wizekat]

Hello,

Beeing an Advanced Physics and Sicence afficionado, but with no real cursus in these matters, I've still been having this idea for a long while :

Starting from the fact that :
"seeing" is merely "capturing" photons reflected by whatever is in front of you;

Covering an object with a surface or enregy field having the property of NOT reflecting light, ie: photons, but instead could calculate the exact direction they are coming from, as well as othe physical properties, AND, on the exact oposite side of the cloaked object, would generate or send the captured photon, or emit a similar photon going in the exact direction with identical speed and other properties;

THEN, we would have achieved INVISIBILITY TO THE HUMAN EYE for the cloaked object !

Yes, I know this sounds rather simplistic, but anyway, if there is out there anyone somewhat more qualified than me, who's been having similar ideas, well i'll be happy to hear from him / her...

Sorry if this sounds "out of topic", i'll be happy to find out what is the right topic...

 

[ZapperZ]

It is not as easy as you think.

The only current possibility that we have right now are using those left-handed metamaterials. Do a search on it. Even then, the bandwidth for such a device is still highly limited. And this is still ignoring the fact that these metamaterial are horribly difficult to fabricate for any considerable size.

Zz.

 

[minorwork]

Look for the Dean Ing technothriller: The Ransom of Black Stealth One. An excellent read that covers the concept. An excellent presentation of the problems you bring up. The only problem is the publisher, Tor. Their books just don't stay together. From the back page:

It weighs only a few thousand pounds, but it's the most sophisticated - and dangerous - aircraft ever designed. The Soviets are determined to learn its secrets. The Americans have planned an ingenious shell game to protect them. But the rules of the game have just been changed. Black Stealth Ones has been stolen -- by a man the CIA killed years before. And he's taken an Agency chief's niece as hostage.

The intelligence community has mobilized every high-tech resource at its disposal in a heartstopping race to capture Black Stealth One before it falls into the wrong hands. There's just one catch: How do you stop a plane that can vanish from sight in seconds?

Reviews

"Read the book now; Some day it might be classified..." "Ing's portrait of Black Stealth One is an extraordinary technical achievement, perhaps the last great breakthrough in stealth technology. It mesmerized me from the first page."
Dr. Timothy Orrok, Technical Staff (Ret'd)
AT&T Bell Laboratories

"Has the reader hanging on to each page...Ing has successfully blended the elements of an old-fashioned chase with a Cold War spy thriller and the almost-science-fact of stealth technology that is making headlines today."
Associated Press

 

[minorwork]

Top and bottom of the craft covered with Organic LEDS controlled by a good computer that when parameter for focal point of the observer will image the LEDs to the view of what is on the other side of the craft. Thus if hovering 5 foot or so above the ocean surface the cameras image the ocean and project on the top surface the ocean image. Also when at altitude the computer could project on the bottom surface an image that to a ground hugger would look like a large bird riding the air currents. 'Course he would have to fly like one. Or a Cessna 150. Or an alien UFO. Or Superman. That be my favorite. Or an Eat at Joes ad. Or just project on the bottom what the top cameras see if the observer was at a specified point below. Lots of computer power that when The Ransom of Black Stealth One was published in 1989 might now be more probable. The OLEDs are here now and the computers?

 

[russ_watters]

Trouble is, that would only work on a single line-of-sight.

 

[minorwork]

Line of sight fools the eye quite effectively. Watch David Copperfield make the Statue of Liberty dissappear. http://video.google.com/videoplay?docid=-779495304265089819&q=copperfield%2C+statue+of+Liberty&total=15&start=0&num=10&so=0&type=search&plindex=0. Line of sight limitation is not trouble but an engineering POV (point of view) problem. First person shooter video games have come a long way since the old Id games Castle Wolfenstein and Doom.

What are these troubles you speak to? Certainly there are limitations of effective use. Parallax issues would necessitate a certain distance from the observer(s) to the image. Note that Copperfield and others control tightly the location of the audience and cameras that the invisibility illusion is maintained.

It is the illusion of invisibility that is desired. Camouflage is just as good for achieving the results desired from invisibility. I may start using the term cloaked. It is easier to type and has achieved some popularity via the Star Trek phenom.

The ability to not only mimic what the cloaked craft blocks from the observers line of sight, but to project in that line of sight any shape desired would make it possible to send a craft appearing to be a threat as a decoy while the real threat approaches appearing to be if not invisible then of a non threatening nature.

In the book by Dean Ing the crafts onboard computer could be set to track an overhead observer and project to that point in real time the scene the observer would see in the cloaked crafts absence. And at the same time track a boat on the oceans surface and project to it a gull or what it would see if the cloaked craft was not there.

Some computer, eh?

 

[russ_watters]

I think you misunderstand the line of sight issue.

Note that Copperfield and others control tightly the location of the audience and cameras that the invisibility illusion is maintained.

Right. In general, though, you won't have control over the line of sight. To someone standing on the other side of the Statue of Liberty, it didn't disappear. It only works along one line of sight at a time, so the object is only cloaked to a single observer at a time. Everyone else seems a misplaced pattern of lights.

 

[minorwork]

Two groups on opposite sides could be made to see the illusion at the same time. Just need two screens is all and the ability to put on the screens the scenes desired.

Well, the matter of control of line of sight is large but I feel that if an airborne tracker can maintain in real time the line of sight long enough to give a laser time to heat the target to malfunction, then the ability has been demonstrated. I'll have to look for the source but I'm pretty sure the military developers have with a lot of trouble accomplished such a few years back.

 

[minorwork]

Well they have not quite shot a ballistic missle down yet but are on course. http://www.boeing.com/defense-space/military/abl/files/DD_Boeing.pdf.

 

[tormund]

I have read, during my extensive studies on the matter., of a device that takes microwaves and bends them in order to mak it appear that the waves are passing right through the object. If this could be modified to bend light waves we could effectively create a cloaking device capable of rendering objects invisible.

 

[minorwork]

I have read, during my extensive studies on the matter., of a device that takes microwaves and bends them in order to mak it appear that the waves are passing right through the object. If this could be modified to bend light waves we could effectively create a cloaking device capable of rendering objects invisible.

Microwaves eh? Pretty close to radar. I've seen some references too, on the pop-science sites. Seems a regular surface (cylinder) would be the ideal. An invisibility cloak? The human body is not regular and is symetric bilaterally only. But if you were in a cylinder of the right composition it might work. Seen any demos?

 

[mgb_phys]

From a talk by one of the radar guys who invented stealth.
If we could make a plane totally invisible, but then we would just have to lookout for pilots moving on their own 100ft off the ground at 600mph.

A major source of radar echo was the pilots head, which forms a nice corner cube for 10-15cm radio waves. His comment was that if only pilots heads could be filled with some nice radar absorbing material instead of whatever was actually in there - it would be much easier to build the planes.

 

[AEM]

There is a relevant article in the 2 January, 2009 issue of Science, page 110, (a Perspectives commentary "Cloaking with Curved Surfaces" is on page 46). The authors of the article are Leonhardt and Tyc. The article is titles "Broadband Invisibility by Non-Euclidean Cloaking".

To quote from the commentary:

"It can be shown that any geometric transformation of space can be translated into optical properties... but the important question remains: How can one build material with the required properties, such as negative refractive index or magnetic behavior at optical frequencies."

 

[Badi]

Another relevant column can be found in the french science magazine "Science & Vie" (October 2008 No. 1093, p49) for those of you who speak some french. The metamaterial is said to be able to "bend" light incident on it for wavelengths around 660 nm. The material is made out of silver nanowires in an Aluminium oxide matrix.