| Scientists build first anti-laser |
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 The anti-laser captures incoming light waves in a cavity. They bounce back and forth until the energy is absorbed and transformed into heat Now is the world's first anti-laser, which extinguishes the light. Behind the achievement is a group of researchers at Yale. A group of physicists at the U.S. Yale University have succeeded in building what they had previously only described in theory: a circuit that absorbs and cancels out the incoming laser beams, an anti-laser simply. In an ordinary laser is used a so-called active medium, such as gallium arsenide, to create a focused beam of coherent light. All light waves have the same wavelength and turns in pace with each other. The anti-laser is instead "loss medium" in the form of a tailor-made cavity in a silicon wafer. When focusing two laser beams in the cavity from opposite directions so caught rays in the cavity. There they are forced to bounce around until all the energy has been absorbed and turned into heat. Scientists call the innovation of one CPA, Coherent perfect absorber. In theory it should be able to absorb 99 999 percent of the incoming light. Fixed in lab experiments are "only" 99.4 percent absorbed so far. The experiment was done with a wavelength in the near infrared region. Scientists hope to adjust the cavity loss and the media to get the same effect with visible light and the infrared frequencies used in fiber optic communications. Eventually the technology can be useful in optical switches, sensors and other components in future computers that communicate with light pulses instead of electrical signals. |
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| Last Updated ( Saturday, 19 February 2011 ) |
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