Scientists at the University of Konstanz in Germany and the National Institute of Standards and Technology (NIST) have demonstrated an ultrafast laser that offers a record combination of high speed, short pulses and high average power. The same NIST group also has shown that this type of laser, when used as a frequency comb—an ultraprecise technique for measuring different colors of light—could boost the sensitivity of astronomical tools searching for other Earthlike planets as much as 100 fold.
Among its applications, the new laser can be used in searches for planets orbiting distant stars. Astronomers look for slight variations in the colors of starlight over time as clues to the presence of a planet orbiting the star. The variations are due to the small wobbles induced in the star’s motion as the orbiting planet tugs it back and forth, producing minute shifts in the apparent color (frequency) of the starlight. Currently, astronomers’ instruments are calibrated with frequency standards that are limited in spectral coverage and stability. Frequency combs could be more accurate calibration tools, helping to pinpoint even smaller variations in starlight caused by tiny Earthlike planets.
Full article: http://www.sciencedaily.com/releases/2008/05/080505224136.htm
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