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A: Fachverband Atomphysik

A 1: Ultra-cold atoms, ions and BEC I (with Q)

A 1.3: Vortrag

Montag, 18. März 2013, 11:45–12:00, B 305

Strontium in an Optical Lattice as a Portable Frequency Reference — Ole Kock, Wei He, Lyndsie Smith, Huadon Cheng, Steven Johnson, Kai Kai, and •Yeshpal Singh — School of Physics and Astronomy, University of Birmingham, Edgbaston Park Road, Birmingham B15 2TT, UK

A major scientific development over the last decade, namely clocks based on optical rather than microwave transitions, has opened a new era in time/frequency metrology. Several Physics Nobel prizes (1997, 2001, 2005, 2012) were awarded for methods that have enabled optical clocks.In optical clocks the (laser) electromagnetic wave beats 10^15 times per second instead of 10^10 as in microwave clocks. Optical clocks have now achieved a performance significantly beyond that of the best microwave clocks, at a fractional frequency inaccuracy of 8.6 *10^-18. The essential techniques used in optical clocks are the confinement of the atoms to regions significantly smaller than the wavelength of light, provision of an environment as free of disturbing influences (magnetic and electric fields, residual gas, black-body fields) as possible, choice of adequate atomic species, and the narrowing of the spectral width of the clock laser to relative levels of 10^-15 and less. With the rapidly improving performance of optical clocks, in the future, most applications requiring the highest accuracy will require optical clocks. They cover the fields of fundamental physics (tests of General Relativity and its foundations), time and frequency metrology (comparison of distant terrestrial clocks, operation of a master clock in space).