The Gaming Den

I found an interesting article in the newspaper at my mom's house... I thought that maybe some people here might be interested.

The Peninsula Daily News/The Daily Telegraph wrote:Invisibility: Concrete Idea

TWO U.S. ELECTRONICS engineers claim to have brought the mythical cloak of invisibility a step closer to reality after announcing proposals for a "shield" that makes objects disappear by reducing the light scattered from them.

The idea, which does not seem to break any of the laws of physics, is explained in the journal Physical Review.

Dr Andrea Alu and professor Nader Engheta of the University of Pennsylvania rely on plasmons, ripples in the oceans of electrons at the surface of every object, to achieve their effect.

If made to oscillate at a certain frequency, the energy from the light is harvested by the plasmon, canceling the light scattered by the object and rendering it "nearly invisible to an observer."

Prof. Engheta says: "There are still important issues to be resolved, but the concept is very exciting."

That would make it non-reflective, not invisible. The object would become a translucent colored region. The absorbance of the substance wouldn't change in this model. So even if you used the magic of plasmons to keep any light from being scattered, the fact is that pigmented compounds inside the object would still absorb various sundry wavelengths of light passing through.

So while you couldn't "see it", you could "visually identify its location".

-Username17

But if properly used in the right lighting or visibility conditions (meaning poor), such a device could render true, perceived invisibility vs. an opposed viewer. Even if the effect is somewhat primitive and even moderately effective at absorbing some light. Mixed with traditional camouflage that is appropriate for the specific background, you could get some decent results from the combo.

A friend of mine's uncle is working on that UoP team.

Wrenfield wrote:But if properly used in the right lighting or visibility conditions (meaning poor), such a device could render true, perceived invisibility vs. an opposed viewer.

You mean like how if you paint yourself the same color as the region behind you, you attain perceived invsibility vs. an opposed viewer?

Now, what it really seems like they are doing is coming up with an electrical way to negate reflectivity, which is going to make stealth easier against otherwise matte or mixed backdrops. "Invisibility" it is not.

At its best, the effect is no better than covering yourself with mud and moss in a jungle. I can already see some industrial uses for it, however. Imagine an electrical field that negates scattering and therefore reduces the minimum size of a laser-cut. If it works, you could miniaturize microcircuits even more.

-Username17

There's a dude in Japan who has invented an invisibility cloak.

Its a real cloak made out of a cloth material akin to a computer flatscreen. Micro-cameras all over the cloak put their input on the other side of the cloak.

Its not invisibility, but worth at least a +10 to Hide.

Guest (Unregistered) at [unixtime wrote:1110940302[/unixtime]]There's a dude in Japan who has invented an invisibility cloak.

Its a real cloak made out of a cloth material akin to a computer flatscreen. Micro-cameras all over the cloak put their input on the other side of the cloak.

Its not invisibility, but worth at least a +10 to Hide.

I saw a picture of that in the papers a couple of years ago. It was actually translucent. Not complete invisible, but getting there.

FrankTrollman at [unixtime wrote:1110940124[/unixtime]]

Wrenfield wrote:But if properly used in the right lighting or visibility conditions (meaning poor), such a device could render true, perceived invisibility vs. an opposed viewer.

You mean like how if you paint yourself the same color as the region behind you, you attain perceived invsibility vs. an opposed viewer?

Now, what it really seems like they are doing is coming up with an electrical way to negate reflectivity, which is going to make stealth easier against otherwise matte or mixed backdrops. "Invisibility" it is not.

At its best, the effect is no better than covering yourself with mud and moss in a jungle. I can already see some industrial uses for it, however. Imagine an electrical field that negates scattering and therefore reduces the minimum size of a laser-cut. If it works, you could miniaturize microcircuits even more.

-Username17

I was thinking more of using it for night-time ops where weapons without heavy visible-energy signatures are used (since I dunno if the gunpowder blast of a firearm would issue forth outside the effect of the surface-plasmon harvesting).

My thinking is:

plasmon field chicanery + traditional camo + poor lighting conditions + stealth weaponry + stealth tactics + elite soldiering = virtual invisibility.

I didn't do so well in Physics 1301, so take this with a grain of salt...

I'm sure most of you know most or all of this, so feel free to skip through to the end (or correct me).

On one level, when light is reflected, it bounces off at an angle equal and opposite to the angle that it came in at ("angle of incidence = angle of reflection").

With a very reflective surface, it looses very little energy in the 'bounce.' For a less reflective surface, if looses more energy, and is maybe bounced around more.

On another level, when light is reflected a photon is absorbed by an atom's electron, which jumps up all excited and then tosses another photon out using the same angle principle stated above (why? I don't know )
In the case of an extremely reflective material (like a conductive metal), the photon released is identical to the photon absorbed, meaning that the light seems to be 'reflected.'

On another level (woo, quantum!) the photon shoots through the electron, exciting it, and the electron shoots out two photons. One is exactly equal to the original photon, save that its waves and troughs are equal and opposite: they cancel each other. The other is the same reflection bouncing off that I've been talking about all along.

So, if you imagine that you could somehow stop the canceling out, you would have perfect trasmission of light through a material. Of course, fucking around with quantum mechanics like that is, as far as I'm concerned, impossible.

And WTF is a "plasmon" anyway?

Ok, so I did a little research and figured out what a plasmon is and why this could work. A plasmon is apparently an electromagnetic wave through a metal, which can of course lower the electron density of a certain area, allowing the transmission of lower-wavelength electromagnetic radiation.

MrWaeseL at [unixtime wrote:1110978047[/unixtime]]

Guest (Unregistered) at [unixtime wrote:1110940302[/unixtime]]There's a dude in Japan who has invented an invisibility cloak.

Its a real cloak made out of a cloth material akin to a computer flatscreen. Micro-cameras all over the cloak put their input on the other side of the cloak.

Its not invisibility, but worth at least a +10 to Hide.

I saw a picture of that in the papers a couple of years ago. It was actually translucent. Not complete invisible, but getting there.

and I found a picture (finally):