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Optical Frequency Standards Based on the Hg Ion

U. Tanaka, Jonas Bergquist, S. Bize, Scott A. Diddams, Robert E. Drullinger, Leo W. Hollberg, Wayne M. Itano, Carol E. Tanner, David J. Wineland

Published Jan 1, 2003• 2 citations
OpenAlex

Abstract

We report on work directed toward the system- atic evaluation of an optical frequency standard based on the - transition of a single, laser-cooled, trapped Hg ion, whose resonance frequency is 1.06 10 Hz. For the purpose of the evaluation, a second Hg standard has been con- structed. In the cooling-laser system built for the second standard, an injection-locking scheme has been applied to a CW Ti-sapphire laser. We also report optical frequency measurements of the clock transition performed over the past 21 months with the first standard. During this term, the variation of the clock transition frequency is found to be less than 1 10 . Index Terms—Injection-locked laser, mercury ion, optical fre- quency standard.

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We report on work directed toward the systematic evaluation of an optical frequency standard based on the /sup 2/S/sub 1/2/-/sup 2/D/sub 5/2/ transition of a single, laser-cooled, trapped /sup 199/Hg/sup +/ ion, whose resonance frequency is 1.06/spl times/10/sup 15/ Hz. For the purpose of the evaluation, a second /sup 199/Hg/sup +/ standard has been constructed. In the cooling-laser system built for the second standard, an injection-locking scheme has been applied to a CW Ti-sapphire laser. We also report optical frequency measurements of the clock transition performed over the past 21 months with the first standard. During this term, the variation of the clock transition frequency is found to be less than /spl plusmn/1/spl times/10/sup -14/.

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We report on work directed toward the systematic evaluation of an optical frequency standard based on the 2 S 1/2 – 2 D 5/2 transition of a single, laser-cooled, trapped 199 Hg + ion, whose resonance frequency is 1.06 × 10 15 Hz. For the purpose of the evaluation, two 199 Hg + standards have been constructed. In the cooling-laser system built for the second standard, an injection-locking scheme has been applied to a cw Ti:sapphire laser. We also report optical frequency measurements of the clock transition performed over the past 21 months with the first standard. During this term, the variation of the clock transition frequency is found to be less than one part in 10 14 .

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We report on the current status of the optical frequency standard based on a single 115In+ ion. A single Indium ion is being trapped in a Paul-Strauble type trap and cooled in combination of Doppler cooling and sideband cooling to its lowest vibrational states. To interrogate the1S0-3P0clock transition with high accuracy we demonstrate a Hz-level laser system resonant to this transition. With the current setup we are able to achieve a measured linewidth of the clock transition of 260 Hz. The statistical uncertainty of the absolute frequency measurement is 3×10-13, limited mainly by our reference frequency standard.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)•Jun 1, 2006•6 citations
We report on work directed toward the system- atic evaluation of an optical frequency standard based on the - transition of a single, laser-cooled, trapped Hg ion, whose resonance frequency is 1.06 10 Hz. For the purpose of the evaluation, a second Hg standard has been con- structed. In the cooling-laser system built for the second standard, an injection-locking scheme has been applied to a CW Ti-sapphire laser. We also report optical frequency measurements of the clock transition performed over the past 21 months with the first standard. During this term, the variation of the clock transition frequency is found to be less than 1 10 . Index Terms—Injection-locked laser, mercury ion, optical fre- quency standard.
We report on work directed toward the systematic evaluation of an optical frequency standard based on the /sup 2/S/sub 1/2/-/sup 2/D/sub 5/2/ transition of a single, laser-cooled, trapped /sup 199/Hg/sup +/ ion, whose resonance frequency is 1.06/spl times/10/sup 15/ Hz. For the purpose of the evaluation, a second /sup 199/Hg/sup +/ standard has been constructed. In the cooling-laser system built for the second standard, an injection-locking scheme has been applied to a CW Ti-sapphire laser. We also report optical frequency measurements of the clock transition performed over the past 21 months with the first standard. During this term, the variation of the clock transition frequency is found to be less than /spl plusmn/1/spl times/10/sup -14/.
We report on work directed toward the systematic evaluation of an optical frequency standard based on the 2 S 1/2 – 2 D 5/2 transition of a single, laser-cooled, trapped 199 Hg + ion, whose resonance frequency is 1.06 × 10 15 Hz. For the purpose of the evaluation, two 199 Hg + standards have been constructed. In the cooling-laser system built for the second standard, an injection-locking scheme has been applied to a cw Ti:sapphire laser. We also report optical frequency measurements of the clock transition performed over the past 21 months with the first standard. During this term, the variation of the clock transition frequency is found to be less than one part in 10 14 .
We discuss frequency standards based on laser-cooled 199Hg+ ions confined in cryogenic rf traps. In one experiment, the frequency of a microwave source is served to the ions' ground-state hyperfine transition at 40.5 GHz. For seven ions and a Ramsey free precession time of 100 s, the fractional frequency stability is 3.3 (2) X 10-13 (tau) -1/2 for measurement times (tau) < 2 h. The ground-state hyperfine interval is measured to be 40 507 347 996.841 59 (14) (41) Hz, where the first number in parentheses is the uncertainty due to statistics and systematic errors, and the second is the uncertainty in the frequency of the time scale to which the standard is compared. In a second experiment under development, a strong-binding cryogenic trap will confine a single ion used for an optical frequency standard based on a narrow electric quadrupole transition at 282 nm. The bandwidth of the laser used to drive this transition is less than 10 Hz at 563 nm.
Microwave atomic clocks have been the de facto standards for precision time and frequency metrology over the past 50 years, finding widespread use in basic scientific studies, communications, and navigation. However, with its higher operating frequency, an atomic clock based on an optical transition can be much more stable. We demonstrate an all-optical atomic clock referenced to the 1.064-petahertz transition of a single trapped 199Hg+ ion. A clockwork based on a mode-locked femtosecond laser provides output pulses at a 1-gigahertz rate that are phase-coherently locked to the optical frequency. By comparison to a laser-cooled calcium optical standard, an upper limit for the fractional frequency instability of 7 x 10(-15) is measured in 1 second of averaging-a value substantially better than that of the world's best microwave atomic clocks.
Research on the development of the optical frequency standard based on trapped and cold 40 Ca + with the 4s 2 S 1/2 -3d 2 D 5/2 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 6.5×10 −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.
We report on the current status of the optical frequency standard based on a single 115In+ ion. A single Indium ion is being trapped in a Paul-Strauble type trap and cooled in combination of Doppler cooling and sideband cooling to its lowest vibrational states. To interrogate the1S0-3P0clock transition with high accuracy we demonstrate a Hz-level laser system resonant to this transition. With the current setup we are able to achieve a measured linewidth of the clock transition of 260 Hz. The statistical uncertainty of the absolute frequency measurement is 3×10-13, limited mainly by our reference frequency standard.