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Optical Atomic Clock: A long look at the captured atoms
February 06, 2008Optical clocks might become the atomic clocks of the future. Their "pendulum", i.e. the regular oscillation process which each clock needs, is an oscillation in the range of the visible light. As its frequency is higher than that of the microwave oscillations of the cesium atomic clocks, physicists expect another increase in the accuracy, stability and reliability.
In the case of one of the candidates for an optical clock which is developed at Physikalisch-Technische Bundesanstalt (PTB), strontium atoms are retained in the interference pattern of two laser beams. In this so-called "optical grating" the atomic "pendulum", i.e. the absorption frequency of the atoms, can then be measured very exactly. For this optical grating clock, the loading of cold atoms into an optical grating has been optimized to such an extent that approx. 106 strontium atoms are loaded into the grating within 150 milliseconds at a temperature of a few microkelvin.
There, the atoms remain stored for over one second and are available for a precision measurement of the optical frequency.
This value would serve for the redefinition of the base unit "second" provided that additional investigations and international comparison show that this frequency can be determined with sufficient accuracy.
Physikalisch-Technische Bundesanstalt (PTB)
This value would serve for the redefinition of the base unit "second" provided that additional investigations and international comparison show that this frequency can be determined with sufficient accuracy.
Physikalisch-Technische Bundesanstalt (PTB)
Atomic Clock Current Events and Atomic Clock News RSSOptical atomic clock becomes portable
You imagine a clock to be different - yet the optical table with its many complicated set-ups really is one. Optical clocks like the strontium clock in the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig could be the atomic clocks of the future; some of them though are already ten times more precise and stable than the best primary caesium atomic clocks.
Ytterbium gains ground in quest for next-generation atomic clocks
An experimental atomic clock based on ytterbium atoms is about four times more accurate than it was several years ago, giving it a precision comparable to that of the NIST-F1 cesium fountain clock, the nation's civilian time standard, scientists at the National Institute of Standards and Technology (NIST) report in Physical Review Letters.
New JILA technique reveals hidden properties of ultracold atomic gases
Physicists at JILA, a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder, have demonstrated a powerful new technique that reveals hidden properties of ultracold atomic gases.
New method to directly probe the quantum collisions of individual atoms
The first demonstration of a fundamentally new method for measuring a particular quantum property of individual atoms will be described in a research paper to be published in the 19 April 2007 edition of the journal Nature.
Atomic clock signals may be best shared by fiber-optics
Time and frequency information can be transferred between laboratories or to other users in several ways, often using the Global Positioning System (GPS). But today's best atomic clocks are so accurate—neither gaining nor losing one second in as long as 400 million years—that more stable methods are needed.
Biologists find biological clock for smell in mice
Biologists at Washington University in St. Louis have discovered a large biological clock in the smelling center of mice brains and have revealed that the sense of smell for mice is stronger at night, peaking in evening hours and waning during day light hours.
Physicists make atomic clock breakthrough
Andrei Derevianko, Kyle Beloy, and Ulyana Safronova sat down six months ago and began work on a calculation that will help the world keep better time. In competition with scientists at the University of New South Wales, the University team led by associate professor Derevianko conducted research that increased the accuracy of atomic clocks, and they did it without running a single experiment.
Mercury atomic clock keeps time with record accuracy
An experimental atomic clock based on a single mercury atom is now at least five times more precise than the national standard clock based on a "fountain" of cesium atoms.
New technologies enhance quantum cryptography
A team of Los Alamos National Laboratory scientists, in collaboration with researchers from the National Institute of Standards and Technology in Boulder, Colo., and Albion College, in Albion, Mich., have achieved quantum key distribution (QKD) at telecommunications industry wavelengths in a 50-kilometer (31 mile) optical fiber.
Tandem ions may lead the way to better atomic clocks
Physicists at the Commerce Department's National Institute of Standards and Technology (NIST) have used the natural oscillations of two different types of charged atoms, or ions, confined together in a single trap, to produce the "ticks" that may power a future atomic clock.
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