%0 Journal Article
%T Optical frequency standard based on a single 40Ca+
%A KeLin Gao
%J Chinese Science Bulletin
%@ 1861-9541
%D 2013
%I 
%R 10.1007/s11434-012-5646-5
%X Research on the development of the optical frequency standard based on trapped and cold 40Ca+ with the 4s 2S1/2-3d 2D5/2 clock transition at 729 nm is reported. A single calcium ion was trapped and laser cooled in the Paul trap and stay in trap for more than 15 days. The linewidth of a 729 nm laser was reduced to less than 10 Hz by locking to a cavity for longer than 50 hours uninterruptedly. The overall systematic uncertainty of the clock transition has been characterized to be better than 6.5กม10 16. The absolute frequency of the clock transition was measured at 10 15 level using an optical frequency comb referenced to a Hydrogen maser, which was calibrated to the SI second through the global positioning system (GPS). The frequency value was 411042129776393.0(1.6) Hz after the correction of the systematic shifts.
%K optical frequency standard
%K single calcium ion
%K systematic uncertainty
%K absolute frequency measurement
%U http://link.springer.com/article/10.1007/s11434-012-5646-5