Reversing And Accelerating The Speed Of Light

Space Daily ^ | Jul 25, 2006 | Staff Writers

[Ben Mugged]

Physicist Costas Soukoulis and his research group at the U.S. Department of Energy's Ames Laboratory on the Iowa State University campus are having the time of their lives making light travel backwards at negative speeds that appear faster than the speed of light.

~snip~ This backward-bending characteristic of metamaterials allows enhanced resolution in optical lenses, which could potentially lead to the development of a flat superlens with the power to see inside a human cell and diagnose disease in a baby still in the womb.

~snip~ In addition, Soukoulis and his University of Karlsruhe colleagues have also shown that both the velocity of the individual wavelengths, called phase velocity, and the velocity of the wave packets, called group velocity, are both negative, which Soukoulis said accounts for the ability of negatively refracted light to seemingly defy Einstein's theory of relativity and move backwards faster than the speed of light.

Elaborating, Soukoulis said, "When we have a metamaterial with a negative index of refraction at 1.5 micrometers that can disperse, or separate a wave into spectral components with different wavelengths, we can tune our lasers to play a lot of games with light. We can have a wavepacket hit a slab of negative index material, appear on the right-hand side of the material and begin to flow backward before the original pulse enters the negative index medium."

Continuing, he explained that the pulse flowing backward also releases a forward pulse out the end of the medium, a situation that causes the pulse entering the front of the material appear to move out the back almost instantly.

"In this way, one can argue that that the wave packet travels with velocities much higher than the velocities of light," said Soukoulis.

[ctdonath2]

Yes. The deduced implication, backed up by later posts, was "if nothing practical comes of this in 7 years then it's worthless, so don't bother."

[evets]

Already been posted... tomorrow!

[Conan the Librarian]

Everybody knows that the Scientist will one day increase the speedlimit on light so that ships can go faster without breaking the law. Saw it on Futurama...so it must be true.

[Just another Joe]

"if nothing practical comes of this in 7 years then it's worthless, so don't bother."

And to a lot of people, that is the attitude.

"What has it done for me today?" is the way a lot of people look at it.
They don't see, or don't know, that a lot of things that they use in their everyday life took longer than 7 years to develop.

My original question was to FReepers interested in this type of thing to see if they had any insights into what might be developed out of this in the shorter term.
If it was misconstrued, I apologize.

[techcor]

The phase velocity of electromagnetic radiation may under certain circumstances exceed the speed of light in a vacuum

Does that cause Cherenkov (sp?) radiation or is that only for particles?

[RightWingAtheist]

I never was totally comfortable with the whole "Light is both a wave and a particle" explanation.

Once you understand relativity, it makes perfect sense.

[freeangel]

Just, wow!

[RightWhale]

Cerenkov radiation occurs when a particle plows into a substance such as water and momentarily exceeds the speed of light in that medium. That causes the weird blue glow around some nuclear reactors that are water damped.

[Ben Mugged]

Cerenkov radiation occurs when a particle plows into a substance such as water and momentarily exceeds the speed of light in that medium

Then the excessive energy that has to be disposed of during the velocity change generates radiation? Is this true of all mediums? When light transitions from water to air to space does it accelerate? Where does it get the energy to accelerate? Does it absorb it from the medium it is leaving?

[King Prout]

this is deeply odd

[RightWhale]

It is not the light that generates Cerenkov radiation but the particle. The light will be generated while the particle exceeds the speed of light in the medium.

[Ichneumon]

Then the excessive energy that has to be disposed of during the velocity change generates radiation? Is this true of all mediums? When light transitions from water to air to space does it accelerate? Where does it get the energy to accelerate? Does it absorb it from the medium it is leaving?

IIRC, light doesn't actually "slow down" in a medium like water, it just takes longer to pass through it because it makes multiple short "pit stops" along the way, but still travels at the same constant velocity between stops.

[sauropod]

review

[spunkets]

"When light transitions from water to air to space does it accelerate?"

No. The velocity of light in any medium, including the vacuum, is fixed. It is fixed, because of the electromagnetic and spacial properties at those coordinates. The velovity of the electromagnetic energy is given by:

c = 1/sqrt(e * e_o * u * u_o)

where e_o and u_o are respectively, the permittivity and permeability of the vacuum. e and u are respectively, the dielectric constant and permeability of the material if present. They represent an interaction strength at each point. That interaction takes time, so energy moving from one point to the next requires a delay, or interaction time at each point. Light emerging from one medium to another doesn't accelerate, it just encounters different interaction times.

[RightWhale]

The speed of light in a medium is related to the refraction it undergoes per Snell's law and the speed is inversely proportional to the index of refraction. It is not internal micro- or pico-reflections but the quality of the medium to sustain the wave characteristics of light that slows light down. The slowing of light to a foot a second in Bose-Einstein concentrate is due to the index of refraction of the medium being very high. The index of refraction of a pure vacuum is 1.0000 . . . by definition. If the index of refraction is negative then the light would go backwards. Of course, what the ultimate reality might be probably can't even be guessed.

[Ben Mugged]

I thought the angle of reflection always equaled the angle of incidence. If the refraction index is negative, the angle of reflection would be less than the angle of incidence and if the refraction index is good enough, could actually equal the angle of incidence. In that case, the refractive material would be the perfect reflector and if standing in front of one, you would see yourself regardless of your viewing angle.

[Alamo-Girl]

Thanks for the ping!

[monkeyshine]

You just don't know what you are talking about. The fact of the matter is

















So there.

[Southack]

"Soukoulis and his University of Karlsruhe colleagues have also shown that both the velocity of the individual wavelengths, called phase velocity, and the velocity of the wave packets, called group velocity, are both negative, which Soukoulis said accounts for the ability of negatively refracted light to seemingly defy Einstein's theory of relativity and move backwards faster than the speed of light."

[Southack]

"Continuing, he explained that the pulse flowing backward also releases a forward pulse out the end of the medium, a situation that causes the pulse entering the front of the material appear to move out the back almost instantly. "In this way, one can argue that that the wave packet travels with velocities much higher than the velocities of light," said Soukoulis."

Is he saying that he can transmit wave packets (read: potential data) faster than C for the length of his negatively-refracting medium?