New material gives visible light an infinite wavelength

Oct 13, 2013
Effective permittivity of a layered Ag/SiN-metamaterial for a variety of layer thicknesses, plotted against wavelength. Credit: Fundamental Research on Matter (FOM)

Researchers from the FOM Institute AMOLF and the University of Pennsylvania have fabricated a material which gives visible light a nearly infinite wavelength. The new metamaterial is made by stacking silver and silicon nitride nanolayers. It may find applications in novel optical components or circuits and the design of more efficient leds. The work will appear on October 13th in Nature Photonics.

The phase velocity and of dictate how light propagates in a material. The phase velocity determines how the peaks and valleys of the wave move in the material, whereas the group velocity describes the transport of energy. According to Einstein's laws, the transport of energy of light can never be faster than the speed of light. Therefore the group velocity is limited. There are however no physical limitations to the phase velocity. When the phase velocity becomes zero, there is no movement of the peaks and valleys of the wave; when it is infinite the wavelength diverges to very large values. In nature however, no with such special properties exist.

Metamaterials

The research team now presents a metamaterial composed of a unit cell structure much smaller than the wavelength of light. By stacking nanoscale layers of silver and a new material is fabricated in which light 'feels' the optical properties of both layers.

The way light travels through matter is dependent on the material permittivity: the resistance of a material against the electric fields of light waves. Because the permittivity of silver is negative and that of silicon nitride is positive, the combined material has a permittivity which is effectively equal to zero. Therefore, it seems that the light experiences zero resistance, and propagates with an infinite phase velocity. The wavelength of the light is nearly infinite.

An electron microscope image of the top side of the fabricated metamaterial. The silver and silicon nitride layers are clearly visible as bright and dark bands respectively. The top surface of the metamaterial is polished using an ion beam to remove excess silver. Credit: Fundamental Research on Matter (FOM)

The researchers fabricated this material using focused ion beam milling, a technique that allows control over the structure of a material on the nanoscale. With a specially built interferometer it was shown that light indeed propagates through the metamaterial with no significant change of phase, corresponding to an almost infinite . This new material may find applications in novel optical components or circuits and the design of more efficient leds.

Explore further: Physicists develop miniature Raman laser sensors for single nanoparticle detection

More information: Experimental realization of an epsilon-near-zero metamaterial at visible wavelengths, DOI: 10.1038/NPHOTON.2013.256

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User comments : 16

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210
1.5 / 5 (16) Oct 13, 2013
Somebody...bring it own home for me.....I cannot quite wrap my mind around 'LIGHT' that has no definite wave length...and still call it light...!

word-
alaberdy
1 / 5 (4) Oct 13, 2013
Somebody...bring it own home for me.....I cannot quite wrap my mind around 'LIGHT' that has no definite wave length...and still call it light...!

word-

i think the article explained it clearly "light propagates through the metamaterial with no significant change of phase"
baudrunner
1.5 / 5 (15) Oct 13, 2013
@210: I feel your pain.

I fail to see how no significant change of of phase corresponds to an almost infinite wavelength. By that reasoning, light traveling through air has no significant change of phase either, therefore all light not otherwise impeded or filtered through media other than air or vacuum will also have an almost infinite wavelength.
LarryD
1 / 5 (1) Oct 13, 2013
If info cannot be carried by the FTL phase how much info can be carried on an infinite wavelength...ref applications. Could such be used as a comparison/standard wavelength for cosmological purposes? Or Geophysical research? Just asking.
sirchick
3 / 5 (4) Oct 13, 2013
Wouldn't it take an infinite amount of time to measure anything that was infinite.
vacuum-mechanics
1 / 5 (20) Oct 13, 2013
The phase velocity and group velocity of light dictate how light propagates in a material. The phase velocity determines how the peaks and valleys of the wave move in the material, whereas the group velocity describes the transport of energy. According to Einstein's laws, the transport of energy of light can never be faster than the speed of light. Therefore the group velocity is limited. There are however no physical limitations to the phase velocity. When the phase velocity becomes zero, there is no movement of the peaks and valleys of the wave; when it is infinite the wavelength diverges to very large values. In nature however, no materials with such special properties exist.

This seems to be the deep knowledge we known about light wave, however we still do not understand its basic principle how light propagates even in vacuum. Maybe this working mechanism could help the research …
http://www.vacuum...21〈=en
ScooterG
1 / 5 (16) Oct 13, 2013
Wouldn't it take an infinite amount of time to measure anything that was infinite.


No. They use accelerated test methods. They simply accelerate "infinite". Get it??
Vert
not rated yet Oct 13, 2013
If this means that the beam of light is perfectly flat, then wouldn't that allow parallel light beams to be used similarly to a vernier caliper, to make minute measurements from an almost infinite distance?
antialias_physorg
3.7 / 5 (3) Oct 14, 2013
Wouldn't it take an infinite amount of time to measure anything that was infinite.

That's why the article says:
Researchers from the FOM Institute AMOLF and the University of Pennsylvania have fabricated a material which gives visible light a nearly infinite wavelength.

Note the 'nearly'.
LarryD
not rated yet Oct 14, 2013
If info cannot be carried by the FTL phase how much info can be carried on an infinite wavelength...ref applications. Could such be used as a comparison/standard wavelength for cosmological purposes? Or Geophysical research? Just asking.

antialias_physorg, quite right! So if I adjust my previous post to 'nearly infinite' do you see a use for an almost 'straight'/'flat' wave? Just how does this affect the E and B fields? Would there be, eventually, a close proximity result in a 'singular' em field?
Although the article seems to be evidence of the opposite would there be a collapse at some point to produce an em singularity...
(Have to admit I have only read about em singularity for the static case and that was a while back and probably 'history' now.)

antialias_physorg
3 / 5 (2) Oct 14, 2013
Depending on how the material can be structured I could envision it as a device for aligning the phase of two beams. I.e. one could decide whether to send a beam through such an area or not - which would shift its phase relative to another beam.
When these two beams meet you then get destructive/constructive interference which is effectively the realization of a logic element via a path-switch and an area patterened as described in the article.
beleg
1 / 5 (3) Oct 14, 2013
Can you envision analogies to this with superconductivity?
What 'meta-object(s)' gives rises to superconductivity?
What does it take to make electrons behave like the photons here?
Flame me for daydreaming...again.
Moebius
1 / 5 (6) Oct 14, 2013
Don't be too surprised if it's discovered that there are metamaterials in nature. If it has a use nature will use it.
VendicarE
4 / 5 (4) Oct 14, 2013
There is no change of phase of the input vs the output. If the input wave is at phase 1/4 then so to is the output wave. It is as if there is no physical separation between the input and output.

Nothing is physically moving, and nothing has infinite wavelength except an abstract computed property.

You could also sweep a light beam across a target a trillion miles away, measure when the first photons arrive at the left of the target, and when they reach the right, and compute that the speed of light across the target was > c.

Nothing moved physically across the target of course yet the computed value is > c.

ViperSRT3g
3 / 5 (2) Oct 15, 2013
There is no change of phase of the input vs the output. If the input wave is at phase 1/4 then so to is the output wave. It is as if there is no physical separation between the input and output.

You could also sweep a light beam across a target a trillion miles away, measure when the first photons arrive at the left of the target, and when they reach the right, and compute that the speed of light across the target was > c.


Ah, so what you're saying is this type of metamaterial could potentially be extremely useful in Quantum Computing because of the interaction (or lack thereof) with the light? Or even seeing what materials the light has passed through between the emitter and receiver?
sirchick
3 / 5 (2) Oct 16, 2013
Wouldn't it take an infinite amount of time to measure anything that was infinite.


No. They use accelerated test methods. They simply accelerate "infinite". Get it??


Obviously I don't get it.
I don't think any human can truly grasp infinity...we would need to live for infinity to know for sure infinity exists, even then you can't know because when do you stop measuring to make a decision that it is infinite... it might stop at some point.