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New Flat Lens Focuses Without Distortion

Posted by timothy on from the ok-now-let-me-choose-my-frames dept.

yahyamf writes "Applied physicists at Harvard have created an ultrathin, flat lens that focuses light without the distortions of conventional lenses. 'Our flat lens opens up a new type of technology,' says principal investigator Federico Capasso. 'We're presenting a new way of making lenses. Instead of creating phase delays as light propagates through the thickness of the material, you can create an instantaneous phase shift right at the surface of the lens. It's extremely exciting.'" And by "ultrathin," they mean it — 60 nanometers thin. The big advantage for this technology, aimed at telecommunications signals, is that "the flat lens eliminates optical aberrations such as the 'fish-eye' effect that results from conventional wide-angle lenses. Astigmatism and coma aberrations also do not occur with the flat lens, so the resulting image or signal is completely accurate and does not require any complex corrective techniques."

9 of 202 comments (clear)

  1. A return to refractive telescopes? by a_hanso · · Score: 5, Interesting

    Does this mean that very large refractive telescopes will make sense again? If we sandwich a few of these with the metasurfaces tuned right, could we build a telescope that is a slab instead of a tube? How about telephoto lenses built into camera phones? Or cheaper orbital telescopes?

    1. Re:A return to refractive telescopes? by Jafafa+Hots · · Score: 3, Interesting

      Flexing may be less of a problem in a telescope than problems with differential cooling of a thick lens.

      They even say to leave your camera out in the outdoor temperature for a while before shooting rather than taking it outdoors from inside, because the temperature difference can distort images during the cooling down phase.

      --
      This space available.
    2. Re:A return to refractive telescopes? by ceoyoyo · · Score: 4, Interesting

      "because the temperature difference can distort images during the cooling down phase."

      If someone told you that they were either way to credulous or thought you were. You may want to let your camera adjust to the ambient temperature (either cooler or hotter), mostly to avoid condensation, which is a pain to wipe off constantly and will make all your pictures look like you took them in the fog. If you're doing astrophotography you want the sensor to be as cool as possible to decrease the thermal noise. But heating or cooling in a lens on a regular camera doesn't affect the image quality noticeably. Unless of course the lens actually shatters, which I've seen happen, but only growing up in northern Canada.

      But if you don't think flexing might be a problem take a piece of plastic wrap, stretch it across a five gallon pail and blow on it. Try and get it tight enough so it doesn't move but also doesn't tear. Now think that this lens is thinner than that.

  2. It's always been possible by Grayhand · · Score: 3, Interesting

    Look at pin hole cameras. They actually lack lenses but focus to infinity. The trick is to filter out the incidental indirect rays that cause the blurring. The downside with pin holes is they only allow in a small amount of light. I'd love to see a fast lenses, something below F2.8 that doesn't require focusing.

    1. Re:It's always been possible by mug+funky · · Score: 3, Interesting

      why go with such big apertures if you want everything in focus? the beauty of such apertures is you can isolate your subject and blur the tits off everything else in the frame.

      sensor dynamic range is increasing all the time - i'd say by the time one of these lenses works for visible light, they'd be unnecessary.

      of course, there'd still be a need to focus with one of these - the focal point depends on where the subject is.

  3. Re:But... by mug+funky · · Score: 3, Interesting

    depends on the effect you want. sometimes the photographer doesn't wish to be flattering.

    i've seen some stunning stuff shot on 16mm film with a 2mm lens up real close. it makes their nose look a metre long and their neck seem far away, but it's often just what you need.

    also, real estate pics.

  4. Re:What about chromatic aberrations? by Skapare · · Score: 3, Interesting

    It's just a giant antenna, minus the feed. Think of a massive yagi array, flattened. Works best in a very narrow spectrum.

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    now we need to go OSS in diesel cars
  5. Co-author checking in. by Mkoms · · Score: 5, Interesting

    Hi everyone. I'm a co-author on the article, and I'd be happy to answer any questions you may have, though probably tomorrow. I'm hoping that this goes better than the last time I tried this (see here: http://slashdot.org/comments.pl?sid=1747464&cid=33185134), where no questions were asked and most of the discussion centered around mildly funny jokes. I appreciate those as much as the next person, but if anyone likes, we can discuss science =].

    1. Re:Co-author checking in. by jeti · · Score: 3, Interesting

      There's a type of lens called Beugungslinse in German. I think the english term is diffraction lens. It is similar to a Fresnel lens, but the size of the structures are below the wavelength of visible light. What are the differences between these lenses, diffraction grates and the type of lens you're working on?