Title :
A Ca optical frequency standard based on ultra-cold atoms
Author :
Helmcke, J. ; Wilpers, G. ; Degenhardt, C. ; Binnewies, T. ; Sterr, U. ; Riehle, F.
Author_Institution :
Phys. Tech. Bundesanstalt, Braunschweig, Germany
Abstract :
With recently developed strategies to reduce frequency offsets due to residual first-order Doppler effects the relative uncertainty of the Ca optical frequency standard at PTB was reduced to 2.7-10/sup -14/. The weighted mean of the optical frequency measured by a harmonic frequency chain and recently by a femtosecond laser comb is (455 986 240 494 154 /spl plusmn/ 13) Hz. The use of ultra-cold atoms prepared by a novel two-stage cooling method will allow to further reduce frequency offsets.
Keywords :
Doppler effect; calcium; frequency standards; measurement uncertainty; optical variables measurement; trapped ions; 455986240494141 to 455986240494167 Hz; Ca; PTB; femtosecond laser comb; frequency offsets; harmonic frequency chain; optical frequency standard; relative uncertainty; residual first-order Doppler effects; two-stage cooling method; ultra-cold atoms; weighted mean; Atom optics; Atomic beams; Atomic measurements; Calcium; Cooling; Frequency measurement; Laser transitions; Optical interferometry; Optical scattering; Ultrafast optics;
Conference_Titel :
Precision Electromagnetic Measurements, 2002. Conference Digest 2002 Conference on
Conference_Location :
Ottawa, Ontario, Canada
Print_ISBN :
0-7803-7242-5
DOI :
10.1109/CPEM.2002.1034764
