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Science

Researchers Create Light Waves That Can Penetrate Even Opaque Materials (phys.org) 38

Posted by BeauHD from the double-penetration dept.
fahrbot-bot shares a report from Phys.Org: Why is sugar not transparent? Because light that penetrates a piece of sugar is scattered, altered and deflected in a highly complicated way. However, as a research team from TU Wien (Vienna) and Utrecht University (Netherlands) has now been able to show, there is a class of very special light waves for which this does not apply: for any specific disordered medium -- such as the sugar cube you may just have put in your coffee -- tailor-made light beams can be constructed that are practically not changed by this medium, but only attenuated. The light beam penetrates the medium, and a light pattern arrives on the other side that has the same shape as if the medium were not there at all. This idea of "scattering-invariant modes of light" can also be used to specifically examine the interior of objects. The results have now been published in the journal Nature Photonics. This method of finding light patterns that penetrate an object largely undisturbed could also be used for imaging procedures. "In hospitals, X-rays are used to look inside the body -- they have a shorter wavelength and can therefore penetrate our skin. But the way a light wave penetrates an object depends not only on the wavelength, but also on the waveform," says Matthias Kuhmayer, who works as a Ph.D. student on computer simulations of wave propagation. "If you want to focus light inside an object at certain points, then our method opens up completely new possibilities. We were able to show that using our approach the light distribution inside the zinc oxide layer can also be specifically controlled."
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Researchers Create Light Waves That Can Penetrate Even Opaque Materials More

Researchers Create Light Waves That Can Penetrate Even Opaque Materials

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  • Could be a big deal (Score:4, Interesting)

    by john83 ( 923470 ) on Tuesday April 13, 2021 @05:13AM (#61267656)
    Techniques that penetrate human tissue, even a few mm, are a big deal in biomedical imaging, e.g. optical coherence tomography, fluorescence imaging, or optophotonics. This could be Nobel prize territory.

    • If you read TFA, it's much too mundane for any prizes. And quite limited too, since you basically limit your spectrum to "what gets through", and you measure that first.

      Also, I think it only works for transmission. If you want to scatter and reflect at something a in deeper tissue, this technique won't work, since it works exactly be eliminating all those scattering/reflecting frequencies.

      • But you could use it for laser scanning straight through tissues, like of hands and feet. This actually already works to some degree, but this would make it work a lot better. It could reduce or even eliminate X-rays of extremities, and possibly even lower limbs.

    • Place I used to work had light waves that could penetrate more than a few mm of human tissue, they even went through notably opaque objects like sheet steel. Mind you for thicker steel they used water rather than light.

  • Light based "radiography"? (Score:4, Interesting)

    by valinor89 ( 1564455 ) on Tuesday April 13, 2021 @05:54AM (#61267696)

    Something that most of us might have experienced is seeing light appear from one side of a finguer or hand to the other when we obscure the apperture of a flashlight. The hand glows, but the bones are not readily apparent. even a fingertip will appear as if there is no bone.

    Could this method be used to create a light source that is transparent to flesh but not to bones and that, critically, is not scattered by the flesh? This could be a huge for medical limb explorations. Just put the light source on the other side of the limb and observe with the naked eye.

    • Re: (Score:2)

      by jbengt ( 874751 )

      Could this method be used to create a light source that is transparent to flesh but not to bones . . .

      Probably not, at lest not in that way. This method does not magically make things transparent. They measure scattering and distortions of wavefronts passing though a particular item and use that information to shape a new wavefront that won't get scattered and distorted, and so will appear on the other side preserving the original image.
      However, might it be extended to be useful to help transmit infor

  • arXiv link (Score:5, Informative)

    by chx496 ( 6973044 ) on Tuesday April 13, 2021 @06:03AM (#61267706)

    Here's the link to the preprint of the paper on arXiv in case anyone wants to read the original paper (most people won't have a subscription to Nature Photonics):

    https://arxiv.org/abs/2010.01075 [arxiv.org]

  • Sugar cubes? (Score:4, Funny)

    by 140Mandak262Jamuna ( 970587 ) on Tuesday April 13, 2021 @06:08AM (#61267712) Journal
    I know they exist. I have even seen them served along with coffee in five star hotels back in India. I have been in the USA for 30 years now. I have not seen sugar cubes served in anywhere. May be they do in country clubs or Ritz may be. If it is in my local Giant Eagle grocery stores, I have not noticed them.

    • My grandma had them at home all her life. It was a farmer household with rustic food and boots with cow manure (when grandma didn't look).

      It's the normal thing for coffee/tea over here. Because you can have an exact amount with just your hands and no spilling crystals anywhere.

      The price difference is negligible. Pressing costs a bit, but packing efficiency saves a bit too. I don't know why you consider them fancy.

      • "Fancy" is probably spillover from the summary:

        such as the sugar cube you may just have put in your coffee -- tailor-made light beams can be constructed

        Read "tailor-made" and it's not that far from thinking "artisanal" [smbc-comics.com].

    • Because of hygiene-paranoia and/or dirty, antisocial people there are no sugar cubes anymore in regular restaurants or cafes, just little bags. Of course, with these it's easier to decide on smaller amounts. Still, cubes are much more civilized and stylish :D

    • > If it is in my local Giant Eagle grocery stores

      In my day, we built Ancient Greek temples out of sugar cubes for seventh-grade projects. Looks like my stores don't even carry them anymore.

      How will kids simulate Poseidon's wrath now?

      • Thou shalt place a bit of ash on top of the sugar cube and maketh it burst into flame with a cigarette lighter.

    • My local supermarket (I live in Northern Virginia and it's a Harris Teeter) stocks them.

    • I recently read that if the lights hits them just right, it passes straight through. The cubes you didn't see? They were right in front of you!

  • They choose all those frequencies that happen to "slalom" between the particles/atoms the best.

    Which are quite a lot, and can be calculated from distortions in previous transmission attempts.

  • We have light that penetrates opaque material, it's called a laser a powerful one lights through steel.

  • Yeah, it's called radio waves. Just a part of the non-visible spectrum. There is nothing new here, and April fools day was two weeks ago

    • It sounds silly, but it's not. A few generations of cellular later and you could have cell towers changing transmission coherence to penetrate buildings specifically to reach your phone. Most broadcasting/communications equipment uses coherent waves. Some form of incoherent transmission could penetrate walls better, maybe paired with some kind of beamforming to target each individual endpoint.

      Maybe it's more than a few generations of cellular now. It sounds as crazy now as beamforming did for WiFi just

  • You've invented the x-ray!

  • Quantum computing quibits are constructed in a sort of ad hoc way these days with many different variations on the theme. I'm curious if an optical quantum computer could use these waves to prevent environmental decoherence?

  • Poorly applied sunscreen = opaque? (Score:4, Informative)

    by laughingskeptic ( 1004414 ) on Tuesday April 13, 2021 @09:59AM (#61268522)
    The max thickness of ZnO in their experiment was 5.2 microns, a sunscreen application is typically 20 microns. In addition, they used a ZnO particle size of 200 nm and red light at 771 nm wavelength. The over the top hyperbole regarding this experiment reaches the level of absurdity. An experiment involving tiny transparent spheres less than 1/3 of the wavelength of the incident light does not translate into seeing deeply into something like a human body.

  • You know horney men are going to use it to view clothed women naked. And then crooks looking to see who is home.

  • Everyone under 50: "Sugar what?"

  • Oppenheimer, Teller, Bethe et al did that in 1945

  • I once saw a 50kW laser in a lab... (Score:3)

    by tigersha ( 151319 ) on Tuesday April 13, 2021 @02:25PM (#61269740) Homepage

    ...penetrating a brick wall. Does this count?

    • Re: (Score:2)

      by sl3xd ( 111641 )

      That depends. If the brick vaporized through the wall fast enough for the generated gas to be inertially contained (and then detonate), it totally counts.

      I wonder if the NIF is powerful enough to vaporize through a tiny hole through a brick wall that quickly...

  • I bet I know what most men immediately thought of, eh, nudge nudge wink wink

  • Seems to me they are shining a light through a translucent diffusing medium. Not saying this doesn't have useful applications, but the headline sucks.
    I am also a little bit reluctant to admit that trial and erroring a particular waveform through a stable layer of crystalline nanoparticles produces a process that would work on dynamic, living, organic tissue. the articles seems to stress the importance of the random arrangement, which definitely does not exist in organic cell structure.
    However this could b

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