Flat lens offers a perfect image

https://www.seas.harvard.edu/news-events/press-releases/flat-lens-offers-perfect-image

by co_pl_te • 14 years ago

128 30 14 years ago

seas.harvard.edu

cs702• 14 years ago

As an amateur photographer with a small collection of DSLR and MILC camera lenses at home, I'm quite excited by this: "In the future we can potentially replace all the bulk components in the majority of optical systems with just flat surfaces." In other words, this will allow large-sensor cameras to get a lot smaller and thinner.

Edit: WRONG! As sbierwagen points out[1], even though the press release states that the technology is "completely scalable" [to different wavelenghts of light], it actually works only with wavelengths greater than that of visible light. Too bad :-(

sbierwagen: Thanks for the clarification.

[1] http://news.ycombinator.com/item?id=4433970

djmdjm• 14 years ago

Sorry, read sbierwagen's comment for the bad news: metamaterials like those used to construct this lens are tuned for very specific wavelengths so unless your photographic aesthetic is centered on a very particular colour of IR then you will be out of luck for quite a while.

sbierwagen2• 14 years ago

Metamaterial lenses, if you can make them in visible-light frequencies, might be useful in the microlens array for light-field cameras, where they could act as both the bayer color filter pattern and as focusing element, and where their excellent optical qualities would be really helpful. (The Lytro light-field camera's lousy optical performance is mostly due to the microlens array: they have to be made of conventional materials, and the only lenses that would fit are singlets, which have chromatic abbertation and barrel distortion out the ass.)

But as the primary light gathering element, no.

mrich• 14 years ago

As a myopic geek I am looking forward to ultra flat glasses :)

sbierwagen2• 14 years ago

  Operating at telecom wavelengths (i.e., the range commonly used in fiber-optic 
  communications), the new device is completely scalable, from near-infrared to 
  terahertz wavelengths, and simple to manufacture.

Ho ho, very clever use of words there. Terahertz is far-far infrared, (1mm to .1mm (1,000,000-100,000nm) wavelength) while NIR is around 1,000nm. Visible light is 740-380nm.

To the best of my knowledge, (this isn't my field) nobody has ever made a visible-light metamaterial. The antennas are too small. There's no real physical reason we can't make red-light metamaterials, the problem is just fabrication. (A parallel can be drawn here between metamaterials, desktop nanofactories, and fusion reactors)

Additionally, it would be tricky to make a panchromatic metamaterial lens: metamaterials are tuned very precisely to one frequency, (color) constrained by the physical size of the antennas, and they can't transmit any others.

soup10• 14 years ago

I don't get why every science article gets negative comments like this. Just because something doesn't have immediate practical applications doesn't mean its not interesting research.

Of course it's annoying when they are overly optimistic(either because of journalists trying to make the finding interesting, or researchers trying to get more funding), but that's to be expected.

DenisM• 14 years ago

Where headline is not accurate, it bears pointing out. I had no idea that this is not in fact a visible light lense.

russell• 14 years ago

It's not an article; it's a press release. They're all the same whether they come from Harvard, MIT or Podunk U.

ChuckMcM• 14 years ago

To the best of my knowledge, (this isn't my field) nobody has ever made a visible-light metamaterial."

You would be wrong, see this CalTech press release: http://media.caltech.edu/press_releases/13341

However the thing that makes this interesting is that every single SFP+ single mode fiber tranciever (and if you've got a datacenter you probably have a lot of those) has a glass lens which focuses the light from the fiber onto the detector. Losses in the system affect how far you can run that fiber and/or how bright the laser at the source end needs to be. So this invention has the potential of making those connections both cheaper (easier to manufacture) and more efficient (no light lost due to abberations in the lens). So that is a pretty big deal.

USC professor Tim Strand was doing research into holographic lenses back in the early 80's. Basically trying to create a white light hologram of a lens system. Cool concept that didn't get far enough unfortunately. (I kept hoping one day we'd have a sticker you put put on your sunglasses and it would turn them into prescription glasses for you.)

jasonwatkinspdx5• 14 years ago

10^3 range of wavelengths sounds pretty damn scalable to me.

Metamaterials for visible light wavelengths do exist. One that got note in the press a few years ago has a negative index of refraction.

Panchromaticity could be accomplished via a color array scheme similar to what is already common in lithographic optic devices.

This not being your area is precisely why you should extend the researches some respect, rather than immediately pouncing on any plausible rhetorical trick to make yourself seem expert when you are not.

jasonwatkinspdx5• 14 years ago

Sorry, upon rereading this it's more grumpy than I like; but in the interests of transparency I won't edit it. Just frustrated at a general trend on hacker news of assuming straw men when it's clear they don't exist from slightly more deliberate reading of the primary source.

batista• 14 years ago

>To the best of my knowledge, (this isn't my field) nobody has ever made a visible-light metamaterial.

http://eurekalert.org/pub_releases/2007-01/dl-mft010407.php?...

http://www.photonics.com/Article.aspx?AID=42007

http://www.popsci.com/science/article/2012-04/nanofishnet-co...

blacksmythe• 14 years ago

From the summary article, it looks like they have made a Fresnel lens, which can also be quite flat but works over a limited wavelength range of light.

In order to achieve broadband operation, the phase change vs wavelength of the metamaterial needs to approximate a large delay. If a large delay is not feasible to implement, this summary is overstating the importance of this result compared to prior technology.

co_pl_te• 14 years ago

Hi, sbierwagen.

This is certainly beyond my field of expertise, but I don't see how the inability of this new lens to focus in the range of visible light detracts from the main point of it being a distortion-free lens whose "focusing power approaches the ultimate physical limit set by the laws of diffraction."

Although I agree that the press release makes it appear as if this will have direct implications on imaging in the lay sense (this isn't going to make a future iPhone the perfect camera), there are certainly applications of such technology that aren't consumer-focused and don't require visible light that stand to benefit from this research.

As blacksmythe notes, the lens created is not your stereotypical refractive lens, but is more along the lines of a Fresnel lens or zone plate. I'd be interested in hearing more about the differences between the two, especially with regard to the limitations of each. Would anyone who read the write up in Nano Letters or has a better understanding care to comment more on the implications?

I agree the press release is a tad sensationalistic and possibly (intentionally) misleading — but what do you expect from a press release? Although the findings presented may not be as earth-shattering as a mass-produceable visible-light metamaterial, I still think it's a noteworthy development that shouldn't be dismissed so easily.

ehsanu1• 14 years ago

OT/Meta: Please use the reply link to post replies, so that coherent threads can be maintained.

th0ma5• 14 years ago

Anyone play with a pinhole on a CCD or CMOS sensor, or otherwise "no" lens? For a non-lens-distorted picture?

vladoh• 14 years ago

As far as I know the problem is that the amount of light that goes trough the hole is very low and you cannot see much or you need a very strong light source.

Sharlin• 14 years ago

Or you have to expose for a long time.

JoshTko• 14 years ago

Couldn't you just put one of these lenses in front of every single CCD subpixel to create a flat lens?

yread• 14 years ago

The article says they have to be tuned to a specific frequency so it wouldn't work for CCDs. But I think that it could be used for projectors. They probably can't zoom though

jws• 14 years ago

You would end up with very little light gathering capacity. The number of photons exposing each pixel would be only the ones emitted from the source that managed to strike the pixel directly. The same as a pinhole camera.

The thing about a lens it is lets you grab a relatively huge area of light and sort it all out so the right bits go to the right pixels.

I already did arithmetic once today (erroneously as it has transpired), so I'll pass on this, but although a metric dumptruck load of photons fly off ov things, when you are 10 meters away, and have an image element the size of a CMOS pixel, there aren't a lot of photons per second to let you sort out 256 levels of intensity without random noise.

wamatt• 14 years ago

One word: Cellphones

danvk• 14 years ago

Will this be useful for Astronomy?

Flat lens offers a perfect image

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