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Tractor Beam?

Posted by michael on from the transporters-to-be-released-with-next-version dept.

shreve912 writes: "No captured Romulan Birds of Prey just yet, but the beam consisting of a helix of twisting laser light is able to seize hold of objects as small as a protein molecule. Scientists believe it will be an invaluable tool for manipulating parts of living cells or components of micro-machines. Holodecks and Borg implants can't be far off! Check out the article."

5 of 8 comments (clear)

  1. Tell us what we want to know! by Dancin_Santa · · Score: 2

    The beam consists of a helix of twisting laser light which is able to seize hold of objects as small as a protein molecule.

    So we know the approximate lower bound of the tractor beam's grip. What's the upper bound? Enquiring minds want to know!

    Dancin Santa

    1. Re:Tell us what we want to know! by ryants · · Score: 2
      What's the upper bound?

      Well, according to the article, it's all on the "microscopic level"... so my guess would be the upper bound and the lower bound are of the same order of magnitude.

      Ryan T. Sammartino

      --

      Ryan T. Sammartino
      "Ancora imparo"

    2. Re:Tell us what we want to know! by caffeinated_bunsen · · Score: 4
      Well, the principle of operation of this (which only rotates objects) and optical tweezers (which move objects but can't rotate them) requires that the object refract light. Strictly speaking, there is no upper bound. But in order to produce a noticable force on a macroscopic object, you'd need far more light (several orders of magnitude) than would be necessary to incinerate said object.

      The force results from the object changing the direction of propagation of photons, and thus changing their momentum. The recoil from this change is what moves the particle. The force is on the same order of magnitutde as the radiation pressure on an opaque object.

      --

      Bugrit! Millenium hand and shrimp!
  2. Re:Is this really a tractor beam? by Dancin_Santa · · Score: 2

    They could possibly use three lasers with the same resonant frequency to "capture" microscopic objects at some point at which the nodes met. When the object is acted upon by another force (gravity), it would essentially bump into a wall of energy on all sides and be forced back into the low energy node. Adjusting frequencies could possibly move the low energy node space towards or away from any particular laser. But I don't know anything about physics so don't rely on me for that kind of stuff.

    Dancin Santa

  3. Short introduction to Optical Tweezers by Anonymous Coward · · Score: 3

    http://www.nbi.dk/~tweezer/introduction.htm