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Nano-Viewing Record Broken
smitty777 writes "Wired magazine reports on a new nanoviewing lens that is capable of viewing objects less than 100 nm across. Rather than attempting to use a 'perfect' lens, this technology uses a porous surface that actually scatters the light. By measuring how it is scattered and setting up lasers to compensate, they're able to 'steer' the light back to the right spot. The abstract from the Physical Review Letters reads: 'The smallest structures that conventional lenses are able to optically resolve are of the order of 200 nm. We introduce a new type of lens that exploits multiple scattering of light to generate a scanning nanosized optical focus. With an experimental realization of this lens in gallium phosphide we imaged gold nanoparticles at 97 nm optical resolution. Our work is the first lens that provides a resolution better than 100 nm at visible wavelengths.'"
... now we might be able to read all the fine print in those EULA's now...
I'm pretty sure I didn't consider that funny at that age either.
The Tao of math: The numbers you can count are not the real numbers.
Wait wait wait... How are you able to get "visible wavelengths" from something that would only be the size of something deep in the Ultraviolet range on the electromagnetic spectrum?
Serious question here, as I'd like to know if this means they're looking at quarterwave light or what...
You can download the article from Arxiv for free here: http://arxiv.org/abs/1103.3643
Basically, the imaging resolution of a lens (typically) has to do with its numerical aperture (NA). A small lens far away has terrible resolution, and vice-versa. The trouble with really high NA lenses is that they are hard to make without distortions. It's easy to make spherical shapes, but aptly named spherical distortion starts to ruin your image once the NA gets high. So what they've done is taken a ground glass surface and put it really close to the object, so that the "scattering lens" subtends close to 2pi steradians. Then they use a spatial light modulator (transmissive LCD screen) to control the phase of their laser beam across many domains to sort of pick out the random scattering elements on the frosted screen that give them the best image. Sort of. There is much additional trickery, but I think that's the jist of it.
There's a difference between an optical lens, which this is supposed to be, and an electronic lens like what you can find in specialized microscopes. Quoting from Wikipedia:
"An electron microscope is a type of microscope that uses a particle beam of electrons to illuminate the specimen and produce a magnified image. Electron microscopes (EM) have a greater resolving power than a light-powered optical microscope, because electrons have wavelengths about 100,000 times shorter than visible light (photons), and can achieve better than 50 pm resolution[1] and magnifications of up to about 10,000,000x, whereas ordinary, non-confocal light microscopes are limited by diffraction to about 200 nm resolution and useful magnifications below 2000x."
Me neither, but kids these days!
Grammar nazis are to this community what excrements are to gold.
SNOM (Scanning Near-field scanning optical microscopes) can easily resolve images at 100 nm at visible wavelengths and have done so for some years now. You can actually buy these microscopes commercially. I'm sure this new method is better than SNOM in some regard, or has the potential to be, but the resolution they achieved is not really a "Nano Viewing Record". More a lens building record.
Non-optical methods like scanning force microscopy have resolved far better than that for years now, of course. Albeit without the ability do do spectroscopic measurements.
Interesting approach though.
The funny lies within the fact that it is so immature. You laugh at the person saying it, not the person it is said about. Even then its still not funny, but every once in a while a joke like this would be somewhat amusing:
A marine and a zealot walk in to a bar and take their seats. The marine looks to his left, then looks to his right. Taco has a tiny penis.
If I can just reach out with my words and touch a butthole, just one, it will all be worth it.
First off physics says this is rubbish. They just re-invented super-resolution enhancement of point sources.
First you need to know why a "perfect" lens is special. When light leaves a small region the shape of the wavefront can be described in a Fourier transform sense as a set of plane waves with various K vectors. Now it turns out that not all K-vectors can propagate to the far field. Ones with K-vectors greater than the reciprocal wavelength simply decay a short distance from the source and never reach the far field.
Thus if you are in the far field and were to time-reverse all the wavefronts you recieved then it would back-propagate to the source but the phase front when it reached the source position will be a blurred version of the source. This is because it's missing all those critical K-vectors. This cannot be replaced because you simply did not know what amplitudes and phases they had.
A perfect lens is special because it captures those decaying k-vectors and effectively (resonantly to conserve energy) amplifies them. You can thus detect this formerly missing information. Therefore you can resolve the sub-wavelength features at full resolution.
SO there's the issue. what they claim is fundamentally not possible. They are claiming they can reconstruct the missing k-vectors. they can't. without nearfield imaging or a perfect lens, physics says those are bye-bye.
But you can "fake" it. this is called super-resolution. If you know something about the source. for example, that it's a point source or collection of isolated point sources then you can impose that information on the data to find the mathematical reconstruction of the image consistent with that information. Thus you can compute the missing K-vectors.
That cannot be done if the thing you are imaging is arbitrary. You have to know something to make up the missing information. It may be that this information is small: e.g. maybe you know the surface is not multi-scattering in depth or you know something about the derivative of the surface curvature or you know something about how it reflects different colors.
But this is "super resolution" enhancement not actual imaging. And that has been done for a long time before this.
Some drink at the fountain of knowledge. Others just gargle.