Precision interferometric frequency measurement of the 674 nm /sup 2/S/sub 1/2/-/sup 2/D/sub 5/2/ transition in a single cold Sr/sup +/ ion

The narrow linewidth 674 nm /sup 2/S/sub 1/2/-/sup 2/D/sub 5/2/ transition in a cold Sr/sup +/ ion confined within an RF Paul trap has been probed using an optically narrowed 674 nm diode laser offset-locked to a second diode laser stabilized to a high-finesse ultra-low-expansion reference cavity. The transition frequency has been measured by means of interferometric comparison with an iodine-stabilized 633 nm He-Ne reference standard. A preliminary value for the /sup 2/S/sub 1/2/-/sup 2/D/sub 5/2/ transition line center is 444 779 045 (9) MHz, limited by residual micromotion and low magnetic field Zeeman splitting.<
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