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Fwd: Article: Lighting a Fire Under Hard Drives

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  • Roger L. Bagula
    ... wrote: Right, left, left. Artist s impression of how laser pulses could replace conventional data transfers to magnetic disks by reversing
    Message 1 of 1 , Jul 1 6:11 AM
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      --- In physical_sciences@yahoogroups.com, "Robert Karl Stonjek"
      <stonjek@...> wrote:

      Right, left, left.
      Artist's impression of how laser pulses could replace conventional
      data transfers to magnetic disks by reversing the spin--and therefore
      the polarity--of their photons.

      Credit: Stanciu et al., Physical Review Letters

      Lighting a Fire Under Hard Drives
      By Phil Berardelli
      ScienceNOW Daily News
      28 June 2007

      In the race to make computers more powerful, magnets may be out and
      lasers may be in. Ultra-rapid pulses of polarized light fired from
      lasers, new tests show, can outperform conventional magnetic data
      writers by as much as two orders of magnitude. The technology could
      form the foundation of a new generation of computers that link lasers
      to their hard drives.
      Long gone are the days when computers were required only to make
      mathematical calculations. Even modest desktop models are now expected
      to handle streaming audio and video from multiple Web sites
      simultaneously, for example. Those functions require huge amounts of
      data to be transferred quickly to and from the hard drive. But current
      data-processing systems, which use magnets to write and read the
      binary code that constitutes computer language, can only work so fast.
      Some users' needs have begun to bump up against the limitations of
      this technology. If computers are to become faster, they'll require a
      different data-transfer system, and the awesome promise of quantum
      computing remains years away.

      Researchers at Radboud University Nijmegen in the Netherlands think
      they've found another candidate. In laboratory experiments, they used
      laser light to write data to a magnetic hard drive at very high
      speeds. The technique works because the photons transmitted by the
      laser actually carry angular momentum, allowing them to interact with
      the hard drive. Also, each laser pulse heats a tiny space on the disk
      just enough to make changing its polarity--thereby storing a bit of
      data--a little easier. The key is reversing the polarity of the laser
      pulses, which can produce the equivalent of either a 1 or a 0 of
      binary code on the disk storage medium.

      The researchers managed to transfer data at intervals of about 40
      femtoseconds, or quadrillionths of a second, about 100 times faster
      than conventional magnetic transfers, the researchers report in a
      paper accepted for publication by Physical Review Letters. One
      drawback is that the footprint of the laser pulse on the disk is about
      5 microns wide, which is considerably larger than the footprint
      produced by existing data-transfer systems. But physics doctoral
      candidate and co-author Daniel Stanciu says the team is working on
      improvements in the technology that should reduce the footprint's size
      to about 10 nanometers, and he expects to see a working prototype
      within a decade.

      "This is one of the most exciting stories in magnetics," says
      physicist Julius Hohlfeld of Seagate Research in Pittsburgh,
      Pennsylvania. Lots of other researchers have tried to employ polarized
      laser light to write data, he says, but everyone failed because the
      magnetic alloys they used for the storage medium did not work. But the
      disk made of gadolinium, iron, and cobalt that Stanciu's team used has
      succeeded. The next challenge, Hohlfeld says, will be to find a
      relatively cheap laser technology that can fire pulses lasting less
      than 100 femtoseconds.

      Source: Science

      Posted by
      Robert Karl Stonjek

      --- End forwarded message ---
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