High-resolution laser microwave double-resonance spectroscopy of hyperfine splitting of trapped 113Cd+ and 111Cd+ ions.

The ground-state hyperfine splittings of laser-cooled 113Cd+ and 111Cd+ ions confined in a linear Paul trap have been measured to be 15 199 862 854.96(0.12) Hz and 14 530 507 349.9(1.1) Hz, respectively, using a microwave-optical double-resonance technique. The results for 113Cd+ agrees with previous measurements very well, and the precision of the 111Cd+ is improved by 7 orders of magnitude compared to the best results reported in the literature. The possibility of a microwave frequency standard based on laser-cooled cadmium ions is also discussed. [ABSTRACT FROM AUTHOR]