LightFocusing Optical Antennas

1
Light-Focusing Optical Antennas

• Groups 25 26
• OMIS 351
• 4/24/08

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What are Light-Focusing Optical Antennas?

• Two rectangles made of gold with rounded edges
  that sit on top of the lasers facet (the area
  that emits the light)
• They are approximately 130nm long and have a gap
  of 30 nm between them

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Who created them?

• Harvard University Researchers led by Professor
  Federico Capasso and Assistant Professor Ken
  Crozier
• Actually named the Plasmonic Laser Antenna

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How are they created?

• The researchers evaporated a gold layer directly
  onto the laser to create the laser nanoantenna
• They then used a focused ion beam to remove the
  gold from unwanted areas to form the antenna
• The researchers used gold for the antenna because
  of the metals high conductivity at optical
  frequencies.
• Also, gold suffers only minimally from problems
  such as degrading or tarnishing that commonly
  affect other metals

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What do they do?

• The antennas allow the laser beam to get around
  the diffraction limit
• A diffraction limit is a law of physics that
  states light beams cannot focus onto a spot whose
  diameter is less than half the lights wavelength

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What do they do continued

• Before these plasmonic laser antennas were
  created, it was only possible to get around the
  diffraction limit in labs.
• Systems that scientists without plasmonic lasers
  were too fragile and complicated to become
  available for practical consumer use.
• This technology can be used with any off the
  shelf laser that are typically used in CD and
  DVD drives.

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Uses

• The first major use for this technology was in
  microscopes
• However, the newest use for these antennas is in
  optical storage
• Companies that are in talks to use this storage
  are Seagate Hitachi Global Storage Technologies

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Other Uses

• Near Field Optical Microscopy
• Heat Assisted Magnetic Recording
• Nanoscale Optical Lithography
• More powerful computer chips and higher
  resolution
• Researchers say the antennas may soon be able to
  manipulate objects as small as atoms

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Optical Storage

• Because this technology allows laser beams to be
  focus on a much smaller spot, its perfect for
  storage
• Instead of increasing the discs ability to hold
  data, these antennas allow data to be packed much
  tighter into a disc

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Optical Storage

• A typical DVD can hold 4.7 gigabytes of data when
  created with a standard laser
• A DVD created with a laser equipped with the
  plasmonic antennas can hold upwards of 3 to 5
  terabytes of data
• This amount of storage is compared to over 750
  movies being held on one DVD that we currently
  use today

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Sources

• http//www.computerpoweruser.com/editorial/article
  .asp?articlearticles2Farchive2Fc07012F28c012F
  28c01.asp
• http//www.plasmonanodevices.org2Fspp32Fdocument
  s2Finvited2F133.pdfeiifAMSIjKGpXcigGN0MX8Agus
  gAFQjCNE0LU8hjy9CxhhFuL5Ftuif5kHqzQsig21ibh8yyW
  mVl2tHCalcYLkg
• http//www.technologyreview.com/read_article.aspx?
  chspecialsectionsscemergingid18295