

Team produces weird optical phenomena - and rewrites the rules of refraction - rickdale
http://www.tgdaily.com/general-sciences-features/58245-team-produces-weird-optical-phenomena-and-rewrites-the-rules-of-refr

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danparsonson
Interesting stuff, but to me it's a bit of a stretch to say that they've
rewritten the rules of refraction, since the basic laws assume ideal
interfaces between media. What they've actually done is created a material so
exotic that that abstraction is no longer sufficiently accurate to describe
it. I imagine QED (<http://en.wikipedia.org/wiki/Quantum_electrodynamics>)
still holds.

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bl
"[I]t's a bit of a stretch to say that they've rewritten the rules of
refraction."

Indeed. It appears more akin to the situation we have with classical and
quantum mechanics: classical (Newtonian) mechanics fairly accurately describe
the behavior of macroscopic objects at relatively slow velocities. We
acknowledge that the system is not valid outside of that range. But since that
range encompasses the bulk of our everyday, practical experience, classical
mechanics are exceedingly useful.

Classical optics are not suddenly outdated with these discoveries. Snell's law
and the lens-maker's formula are just as relevant as they were yesterday. We
just need to add a few more terms to the equation if we etch a gradient of
nano-scale resonators to the surface of our optical element. (Boy, do I feel
like Geordi in _Star Trek_ reading that last sentence aloud.)

Negative index of refraction materials are not quite new: wikipedia indicates
that they are already being used in commercially-available products
(<http://en.wikipedia.org/wiki/Negative_index_metamaterials>). For me, the
most exciting application is creating a lens that circumvents the diffraction
limit that limits optical imaging resolution. Right now, the most
sophisticated, expensive microscope objective lenses can just barely resolve
sub-cellular structures only under very particular conditions (i.e., not
alive). A diffraction- _un_ limited "superlens" made out of this stuff could
enable us to see even smaller objects under physiological conditions. It would
be fantastic if we could capture the release of individual neurotransmitter
vesicles at a diseased synapse, for example.

Besides negative index materials, there are a whole class of non-linear optics
(<http://en.wikipedia.org/wiki/Nonlinear_optics>) that allow engineers to do
all sorts of funky things in their instruments, like doubling the light
frequency or self-focusing.

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Tloewald
This actually sounds both revolutionary and immediately practical for lens
design. Covering lens with gold nano antennae sounds expensive, and I assume
the surface is delicate, but thin spectacle lenses and super lightweight
camera lenses are an obvious result.

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andrewcooke
absolutely. you could make much more compact "telephoto" lenses too. or
connect "bifocals" to the nerve that controls eye focussing and have glasses
that automatically focus to the correct distance (yes, i am getting old). or
stationary solar collectors that adjust to the moving sun (or that still move
but self-correct for distortions and support flexure). or a new kind of
electronic ink. or...

this is huge, yet the report covers just silly mirrors... weird.

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Someone
Many of those ideas require not only that we can make this stuff in bulk at
low prices, but also that we can dynamically change the stuff after production
at high speed. I did not read that in the article. Did I browse it too fast?

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andrewcooke
ah. maybe i misread the article. where it says antennas i assumed they were
active. but if they're just passive (conductive) elements then you're right. i
guess that is more likely :o(

[edit:] that would certainly explain why they only mentioned silly mirrors!

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mbyrne
Isn't a fresnel lens really just an non-idealized boundary layer too?
<http://en.wikipedia.org/wiki/Fresnel_lens>

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thirdhaf
Correct, but with the caveat that it only really works along the optical axis.
Off-axis you get horrible artifacts. If I recall correctly these metamaterials
do not have that limitation.

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dhpye
How is this new? Surface plasmon resonance effects with gold are, I'd thought,
an exciting but well-understood phenomenon in nanotech.

Using gold nanoparticles to achieve unique photonic effects has been done
since the Roman Empire and the Lycurgus Cup (this artifact used relativistic
behaviors of gold to show two different colors, depending on the light source
being either reflected or refracted)

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spyder
I'm not sure this rewrites any rules, it seems "just" nanooptics when surface
structure with patterns below the wavelength of the light is reflecting,
refracting or diffracting the light.

