Title :
Development of optical frequency standards based upon the 2 S1/2-2D5/2 transition in 88 Sr+ and 87Sr+
Author :
Barwood, Geoffrey ; Gao, Kelin ; Gill, Patrick ; Huang, Guilong ; Klein, Hugh A.
Author_Institution :
Nat. Phys. Lab., Teddington, UK
fDate :
4/1/2001 12:00:00 AM
Abstract :
Recent work is presented on the development of an optical frequency standard, based on the 2S1/2-2D5/2 “clock” transition at 674 nm in two isotopes of strontium. A≈200 Hz linewidth 674 nm laser has been frequency-stabilised to the centre of the 2S1/2-2D5/2 transition in two 88Sr+ ions, separately confined in two RF traps. The frequency locking algorithm for control of the laser frequency to the transition using the two ions is described. The mean difference of the frequency observed in the two ions is 34(33) Hz, where the number in parenthesis is the standard uncertainty. The Allan deviation of the difference frequency stability was observed to range from 10 Hz to 50 Hz at 30 s. In 87Sr+, there are “clock” transitions independent of the first order Zeeman shift; laser cooled 87Sr+ ions have been observed in a new trap with an oven containing isotopically enriched 87Sr
Keywords :
Zeeman effect; clocks; frequency standards; isotope effects; laser cooling; laser frequency stability; optical variables measurement; particle traps; positive ions; strontium; trapped ions; 10 to 50 Hz; 200 Hz; 30 s; 674 nm; 2S1/2-2D5/2 transition; 87Sr+; 88Sr+; Allan deviation; RF traps; Sr; clock transition; clock transitions; control; difference frequency stability; first order Zeeman shift; frequency locking algorithm; frequency-stabilised laser line; isotopes; isotopically enriched 87Sr; laser cooled ions; laser frequency; mean difference; optical frequency standards; oven; standard uncertainty; transition; Frequency; Laser transitions; Laser tuning; Optical control; Optical harmonic generation; Optical interferometry; Optical pumping; Particle beam optics; Standards development; Strontium;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
