Plasmonic Cloaking Technology
Straight out of Sci-Fi... the invisibility cloak gets some scientific papers...
Achieving transparency with plasmonic coatings
Aside from never having heard of plasmons (though the world of 3d animation has a metaphor for "surface normals" which do impact the local surface at specific points in the mesh), I'm scratching my head a bit about this, but it does appear to be a legitimate scientific paper submitted for actual peer review.
And given the recent resurgence in interest in camo (including design books on its history), it doesn't surprise me that this might generate some buzz.
Too bad they don't have demo images, but maybe successful tests would be invisible.
Achieving transparency with plasmonic coatings
Quote:
The proposal involves using plasmons -- tiny electronic excitations on the surfaces of some metals -- to cancel out the visible light or other radiation coming from an object.
"A proper design ? may induce a dramatic drop in the scattering cross-section, making the object nearly invisible to an observer," Nader and Alu write in a scientific paper that was made available to the public Feb. 14.
But cloaking ability would depend on an object's size, so that only with very small things -- items that are already microscopic or nearly so -- could the visible light be rendered null. A human could be made impossible to detect in longer-wavelength radiation such as microwaves, but not from visible light.
A spaceship might be made transparent to radio waves or some other long-wavelength detector.
The idea is in an infant stage but appears not to violate any laws of physics, according to an article Monday in [email protected], an online companion to the journal Nature, which provided advance copies of the story to reporters.
"The concept is an interesting one, with several important potential applications," John Pendry, a physicist at Imperial College in London in the UK, told the publication. "It could find uses in stealth technology and camouflage."
The proposal involves using plasmons -- tiny electronic excitations on the surfaces of some metals -- to cancel out the visible light or other radiation coming from an object.
"A proper design ? may induce a dramatic drop in the scattering cross-section, making the object nearly invisible to an observer," Nader and Alu write in a scientific paper that was made available to the public Feb. 14.
But cloaking ability would depend on an object's size, so that only with very small things -- items that are already microscopic or nearly so -- could the visible light be rendered null. A human could be made impossible to detect in longer-wavelength radiation such as microwaves, but not from visible light.
A spaceship might be made transparent to radio waves or some other long-wavelength detector.
The idea is in an infant stage but appears not to violate any laws of physics, according to an article Monday in [email protected], an online companion to the journal Nature, which provided advance copies of the story to reporters.
"The concept is an interesting one, with several important potential applications," John Pendry, a physicist at Imperial College in London in the UK, told the publication. "It could find uses in stealth technology and camouflage."
Aside from never having heard of plasmons (though the world of 3d animation has a metaphor for "surface normals" which do impact the local surface at specific points in the mesh), I'm scratching my head a bit about this, but it does appear to be a legitimate scientific paper submitted for actual peer review.
And given the recent resurgence in interest in camo (including design books on its history), it doesn't surprise me that this might generate some buzz.
Too bad they don't have demo images, but maybe successful tests would be invisible.
Comments
Seriously, though... there is a theoretical grounding in this work that suggests a variety of 'cloaks' depending on the material, the coating, and the wavelengths involved... invisible to infrared, visible, or ultraviolet and beyond might be practical on other levels.
Trek like Plasmas can 'cloak' From July 2000
"In theory, a plasma could deflect a particle beam or laser attack," Laroussi says. "It depends on what you?re shooting at it and how high you can tune the plasma frequency. That doesn?t mean it?s easy or practically achievable, particularly with a cold plasma. It?s a tough requirement to meet at present."
Cloaking mirrors
A nearer-term application is cloaking. With the proper adjustments, a plasma can be made into a kind of energy mirror, reflecting back or away incoming electromagnetic waves, such as those emitted from ground-based radars. In essence, any spacecraft outfitted with this kind of plasma field would be completely cloaked from the probing attentions of radar operators.
"The idea is to deflect or absorb the energy completely," Laroussi said. "If you absorb the energy --- completely dissipating it within the plasma --- the radar doesn?t see anything. Nothing reflects back."
I have the explanation: Plasmons are different than Plasmas. An electromagnetic wave encountering a surface (even bouncing off of it), will have a component of its electric field leak into the surface since electric fields are smooth over all space. This oscillating field within the surface is the plasma oscillation, the formal particles that arise from the quantization of these oscillations are the plasmons. Each surface has a frequency associated with its plasmon. The electric fields encountering a surface that have a higher frequency than the surface plasmon will be transmitted, those with lower frequency will be reflected.
Originally posted by Scott
Of course the wavelength and the size of the object is the key. It seems to make things that are almost transparent even most almost transparent.
Well, if it can block mm wave, then it can block radar, which means you can make steath planes with lots of manuverability.
Originally posted by hardeeharhar
ok Curiousuburb,
I have the explanation: Plasmons are different than Plasmas. An electromagnetic wave encountering a surface (even bouncing off of it), will have a component of its electric field leak into the surface since electric fields are smooth over all space. This oscillating field within the surface is the plasma oscillation, the formal particles that arise from the quantization of these oscillations are the plasmons. Each surface has a frequency associated with its plasmon. The electric fields encountering a surface that have a higher frequency than the surface plasmon will be transmitted, those with lower frequency will be reflected.
I know they're different.
I was posting the older link because the wave bending/absorption parts seem to address similar theoretical angles.
The new version, plasmons, seems capable of a wider range of potential cloaks, if only because the cold plasma described in the older story has limiting conditions and environments based on energy, etc.
My brief scan of the new paper suggested plasmons don't require anything near the power input to perform a similar function, but as I've noted, I'm not fully grokking the new theory yet.
Originally posted by curiousuburb
I know they're different.
I was posting the older link because the wave bending/absorption parts seem to address similar theoretical angles.
The new version, plasmons, seems capable of a wider range of potential cloaks, if only because the cold plasma described in the older story has limiting conditions and environments based on energy, etc.
My brief scan of the new paper suggested plasmons don't require anything near the power input to perform a similar function, but as I've noted, I'm not fully grokking the new theory yet.
Plasmons don't require energy at all, unless there are materials that need energy to obtain a specific plasmon frequency.
ah whatever. its 3am and i am goin to sleep. peace y'all and keep reaching for the skies... or stars... galaxies... or whatever...