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starship-design: Photonic Computers....
THE FIRST 3D PHOTONIC CRYSTAL operating at a
wavelength of 1.5 microns, the all-important preferred wavelength
for light traveling down optical fibers, has been devised by
scientists at Sandia (Shawn Lin, slin@sandia.gov). Basically, a
photonic crystal is to light what a semiconductor is to electrons:
some photon energies are permitted while others are excluded.
The exclusion comes about by a careful interleaving of materials
with very different indices of refraction. The Sandia crystal is
actually a tiny pile of criss-crossed polysilicon rods with air in
between. Photonic crystals will be ingredients in future optical
transistors---by deflecting light they will be able to act as optical
switches at THz speeds; by trapping light they will be able to
produce optical amplification within cavities. The crystals will
also be part of other optical integrated circuit components such as
low-power nanolasers and as waveguides. (Optics Letters, 1 Jan
1999; see also Physics Today, Jan 1999.)
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