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Shark Biotech

First Liquid-Cooling Laser Could Advance Biological Research (washington.edu) 55

Zothecula writes: In a world where lasers are sci-fi's weapon of choice for melting away an enemy spaceship, researchers at the University of Washington have swum against the current and produced the first laser capable of cooling liquids. " They demonstrated that the laser could refrigerate saline solution and cell culture media that are commonly used in genetic and molecular research. To achieve the breakthrough, the UW team used a material commonly found in commercial lasers but essentially ran the laser phenomenon in reverse. They illuminated a single microscopic crystal suspended in water with infrared laser light to excite a unique kind of glow that has slightly more energy than that amount of light absorbed. This higher-energy glow carries heat away from both the crystal and the water surrounding it." The technology could be especially useful for slowing down single cells and allowing scientists to study biological processes as they happen.
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First Liquid-Cooling Laser Could Advance Biological Research

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  • by xxxJonBoyxxx ( 565205 ) on Wednesday November 18, 2015 @12:17PM (#50955413)

    >> lasers are sci-fi's weapon of choice for melting away an enemy spaceship

    No, I think lasers are sci-fi's weapon of choice for whittling down deflector shields.

  • by gcnaddict ( 841664 ) on Wednesday November 18, 2015 @12:25PM (#50955485)
    and Mr. Freeze's weapon of choice has finally arrived.
  • Wow, that sounds awesome ... I might have to RTFA even.

  • by nimbius ( 983462 ) on Wednesday November 18, 2015 @01:02PM (#50955795) Homepage
    Originally we'd set out for a liquid cooled laser that could be affixed to a large mobile rigging and dynamically targeted while immersed in a saline coolant. this proved difficult due to budgetary and logistics constraints (our director was none too pleased.) However we found a similar biomedical project had succeeded in mounting a laser to a subspecies of the Dicentrarchus labrax with only mild side effect of distemperment.
  • Anti-stokes shift (Score:5, Informative)

    by Anonymous Coward on Wednesday November 18, 2015 @01:08PM (#50955841)

    Aside from the science fiction spin of the summary, the ACTUAL science going on here is called an anti-Stokes shift. When light is absorbed and re-emitted, more commonly some of the light energy is converted to heat (phonons), resulting in the emitted light having slightly longer wavelength (Stokes shift). If there is a strong resonance in absorption at a particular wavelength, emitted light will tend to be closer to the resonant wavelength, even if the absorbed light is of lower energy and requires absorbing heat (a phonon) to generate the higher energy photon for emission.

    https://en.wikipedia.org/wiki/Stokes_shift

    • by slew ( 2918 ) on Wednesday November 18, 2015 @02:25PM (#50956579)

      FWIW, they've been doing laser-doppler cooling for a while (all the articles you hear about cooling atoms down near absolute zero generally used laser-doppler cooling). This anti-stokes technique is very similar to the laser-dopper cooling technique in that both involve on average the emission of photons at higher mean energy than those absorbed.

      In the case of laser doppler cooling, you illuminate a batch of atoms with a laser from multiple directions at a slightly lower frequency than a transitional energy state. Atoms that are thermally in motion, but are instantaneously moving towards one of the lasers will absorb more photons (because doppler blue-shift makes the atom see the slightly higher frequency matching its transition energy state from the laser if it is moving towards from laser) causing the atom to lose net momentum in that direction and become slightly cooler (mostly because the photon will be re-emitted in a random direction).

      In the case of the anti-stokes technique, you need to construct a system that has florescence (emits light a certain frequency when excited) with a bandgap, you then need to pump the energy into the system at the lower frequency. The trick (which is what makes this hard), is that the system needs to be tuned so that the energy you pump in is more efficiently converted into florescence energy than general thermal heating and the photons that are released by florescence can efficiently leave the system to avoid secondary heating.

      Anti-stokes is interesting because it has the potential to be able to cool things microscopically (rather than at the atomic scale only).

      AFAIKT, this team pulled out quite a few stops to setup this system. Apparently, they setup a laser trap [wikipedia.org] to localize the florescent crystal (doped-YLF) and the "liquid" was D2O (deuterium or heavy water) to get the right thermal gradients for the laser trap for their experiment.

      If you are interested, you can read about it here [arxiv.org].

  • I challenge you to find me one person who successfully made it past that headline without thinking "Haven't liquid cooled lasers existed since the laser was first discovered?"

  • by mpoulton ( 689851 ) on Wednesday November 18, 2015 @01:58PM (#50956315)
    "To achieve the breakthrough, the UW team used a material commonly found in commercial lasers but essentially ran the laser phenomenon in reverse. They illuminated a single microscopic crystal suspended in water with infrared laser light to excite a unique kind of glow that has slightly more energy than that amount of light absorbed."

    That is the most detailed explanation in the article of what this phenomenon is and how it works. No names, either for the phenomenon or the materials involved. No numbers, or even quantitative comparisons. No links to the actual research. Who do they think reads this stuff? Random people aren't looking at long-form articles on research posted to university websites. Their whole audience would appreciate a lot more detail than they're giving us.
    • by Anonymous Coward

      This might be their paper: http://arxiv.org/abs/1503.07265

      "The cold Brownian motion (CBM) analysis of individual YLF crystals indicates local cooling by >21 C below ambient conditions suggesting a range of potential future applications."

    • Here is how I understand it. Imagine you have a bunch of fat kids on swings. The swinging represents the kinetic motion of the atoms. If you measure the motion of each kid carefully and shoot a tennis ball at the kid when they are traveling towards you, you can slow them down. If you shoot enough balls at them you can slow them nearly to a stop.

      Replace fat kids with the atoms in this crystal and tennis balls with photons and you have your cooling laser.

  • Chris Knight at Pacific Tech discovered this laser technology years ago..
    • Naa, his laser was used to pop popcorn, so therefore it was heating the foil.

  • Could the be the beginning of my dream of reverse "microwave" appliance that could quickly cool food?

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