Invisibility?

[pljames]

The Japanese has said they now have made a copper wire...disappear. Shades of Spock! How do they do that? pljames

[Klaynos]

If this is the same story I know about it is making it disapper for a specific frequency of microwaves. It is a metamaterial that has specific resonant properties for certain frequencies so it acts in such a way as not being there.

 

It probably uses a combination of surfance plasmon modes and phase resonances, and possibly some other resonances.

[pljames]

How will this effect say, pilots of a aircraft? What about the

color spectrum and the atoms in objects like copper and human? pljames

[Edtharan]

This could be good to, block mobile phones in cinamas and hospitals. The material could be tuned to the frequencyis of mobils and then have the signals diverteed around the building (essentially make the building invisible to the mobile phone frequencies).

 

As for planes, a stealth plane that was tuned to the specific frequencies of a Radar would become invisible to it, better than the current stealth technologies we have today.

[YT2095]

Sir John Pendry has also made significant steps towards this goal, might be worth a google search

[Klaynos]

How will this effect say, pilots of a aircraft? What about the

color spectrum and the atoms in objects like copper and human? pljames

 

If the waveguiding is done correctly then nothing inside should matter.

 

This technology is a very very long way off of working in the optical domain, and we're not too close with microwaves for aircraft mainly because engineering these devices to cover all the aircraft is a massive task even before you have to build in the fact the aircraft has to fly.

[pljames]

I keep hearing the word morals ringing in my ears when the word invisibility is spoken or written in this case. I totally understand spying on our enemies with this new technology...but couldnt big brother also use it against us, in justice, everything in our private world? Is this such a good technology while it might be used...against us?

pljames:confused:

[christian]

The main problem is that the microwave spectrum is very small and the human color spectrum is very large. We would have to make a metamaterial that would be able to resiliant to that spectrum.

[swansont]

The main problem is that the microwave spectrum is very small and the human color spectrum is very large. We would have to make a metamaterial that would be able to resiliant to that spectrum.

 

Not sure how you are using large and small here. Microwaves are longer wavelengths than visible light. While the definitions of sections of the spectrum are somewhat fuzzy, microwaves are generally considered to cover from about 1 GHz to a few hundred GHz, or a little over two orders of magnitude. Visible light doesn't even span an octave (factor of two). So neither the wavelength nor the span of the spectrum of visible light is larger than that of microwaves.

[Klaynos]

I agree completely with swansont, and would like to add.

 

The biggest problem is fabrication of metamaterials for optical devices as the features normally have to be subwavelength, which for microwaves is quite trivial, you can do it with a lump of metal and a saw But for optical devices a relatively 'simple' metamaterial of 0.5mm square can take more than a day to produce accurately. And this time increases massively for metals of a greater thickness, and the accuracy deteriates.