NIST Develops a new generation of frequency and time standards. (News Briefs).NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. staff members in Boulder, in collaboration with the Max Planck Noun 1. Max Planck - German physicist whose explanation of blackbody radiation in the context of quantized energy emissions initiated quantum theory (1858-1947) Max Karl Ernst Ludwig Planck, Planck Institute in Germany, have demonstrated for the first time operation of an optical frequency standard with a microwave output. Their work signals the introduction of a new generation of atomic clocks atomic clock, electric or electronic timekeeping device that is controlled by atomic or molecular oscillations. A timekeeping device must contain or be connected to some apparatus that oscillates at a uniform rate to control the rate of movement of its hands or the with potential performance well beyond those in operation today. This first demonstration of an optical clock with a microwave output, reported in the August 3 issue of Science, involves an optical frequency standard coupled to a new optical-frequency synthesizer synthesizer Machine that electronically generates and modifies sounds, frequently with the use of a digital computer, for use in the composition of electronic music and in live performance. that bridges an octave in the optical spectrum and provides for a direct microwave output that is phase locked to the optical standard. The potential relative uncertainty of the optical clock is 1 X [10.sup.-18], a factor of 1000 better than today's best standards. Essential components of this standard include a single trapped mercury ion in a cryogenic trap, an ultra-stable laser used to probe the transition in the mercury ion, and a femtosecond laser system that produces a frequency comb A frequency comb is it the graphic representation of the spectrum of a mode locked laser. An octave spanning comb can be used for a mapping radio frequencies into the optical frequency range or it can be used steer a piezoelectric mirror within a carrier envelope phase correcting spanning a full octave in frequency. In comparisons with a laser-cooled calcium optical standard, an upper limit for the fractional instability of 7 X [10.sup.-15] was measured in a 1 s averaging interval, which is significantly better than that of the worlds best microwave atomic clock. CONTACT: Jim Bergquist, (303) 497-5459; bergquist @boulder.nist.gov. |
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