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 Photonic Crystal (SEM)
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Photonic
Crystals: New Future for Optoelectronics (11/18/02 10:56 AM EDT) Just over a decade ago it was suggested that complex structures could be formed which could forbid the propagation of light for a range of energies. This groundbreaking discovery has paved the way for researchers around the world to fabricate increasingly smaller crystals, known as photonic bandgap (PBG) structures that trap as much as 95% of certain frequencies of light sent into them. This is a vast improvement compared to the 30% trapped by the conventional waveguides. Additionally, the small PBG structures can bend the light in a fraction of the space needed by conventional waveguides, and an obvious area where the control of emission in this way can significantly benefit device performance is in the area of optoelectronics. Naturally interest has now turned towards incorporating two and three dimensional PBG material into cavity devices in an attempt to realise even greater improvements in performance. In addition to the practical considerations, the availability of numerical methods is clearly important for the design of such complex structures. Photonic bandgap devices allow control of electromagnetic radiation that will enable scientists to develop increasingly smaller, more precise lasers for medical use. Photonic crystals will also play a vital role in optical communications, such as the Internet. With the increasing growth of information technology and the Internet, optical fibers operating at 1.5-micron wavelengths are being employed for high-bandwidth communications. Optic-fiber backbones are perhaps the only viable choice for integrating the large amounts of data and video in the evolving Internet marketplace. Manipulating, switching, and multiplexing optic-fiber channels is an area where photonic crystals are expected to have an important role. Photonic crystals can be tailored to have no losses with certain wavelength bands, which permits building high-efficiency optical components with novel photonic crystal-based designs. All-optical computing will lead to an improvement of computing power by several magnitudes over existing technology. Optical computing involves the use of photons rather than the electrons now used by desktop computers to pass information. However, as more circuits are included on new chips, they become more and more difficult to cool. Photons are faster and cooler than electrons, but researchers have been unable to bend useful photonic frequencies through the millions of turns on a single chip without losing much of the information. Photonic crystal-based devices could solve this problem. DOE  
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