We perform quantum logic spectroscopy with a 27 Al + / 40 Ca + mixed ion crystal in a linear Paul trap for a measurement of the intercombination transition in 27 Al + . Towards this end, Ramsey spectroscopy is used for probing the transition in 27 Al + and the clock transition in 40 Ca + in interleaved measurements. By using the precisely measured frequency of the clock transition in 40 Ca + as a frequency reference, we determine the frequency of the intercombination line to be = 1 122 842 857 334 736 (85) Hz and the Landé g -factor of the excited state to be = 0.428 133(2).
We perform quantum logic spectroscopy with a 27 Al + / 40 Ca + mixed ion crystal in a linear Paul trap for a measurement of the intercombination transition in 27 Al + . Towards this end, Ramsey spectroscopy is used for probing the transition in 27 Al + and the clock transition in 40 Ca + in interleaved measurements. By using the precisely measured frequency of the clock transition in 40 Ca + as a frequency reference, we determine the frequency of the intercombination line to be = 1 122 842 857 334 736 (85) Hz and the Landé g -factor of the excited state to be = 0.428 133(2).
We report the realization of quantum logic spectroscopy on the 1 S 0→ 3 P 0 clock transition of a single 27 Al + ion. This ion is trapped together with a 40 Ca + ion in a linear Paul trap, coupled by Coulomb repulsion, which provides sympathetic Doppler laser cooling and also the means for internal state detection of the clock state of the 27 Al + ion. A repetitive quantum nondemolition measurement is performed to improve the fidelity of state detection. These techniques are applied to obtain clock spectroscopy at approximately 45 Hz. We also perform the preliminary locking on the 1 S 0 → 3 P 0 clock transition. Our work is a fundamental step that is necessary toward obtaining an ultra-precision quantum logic clock based on 40 Ca +-27 Al + ions.
We report, for the first time, laser spectroscopy of the 1S0-->3P0 clock transition in 27Al+. A single aluminum ion and a single beryllium ion are simultaneously confined in a linear Paul trap, coupled by their mutual Coulomb repulsion. This coupling allows the beryllium ion to sympathetically cool the aluminum ion and also enables transfer of the aluminum's electronic state to the beryllium's hyperfine state, which can be measured with high fidelity. These techniques are applied to measure the clock transition frequency nu=1,121,015,393,207,851(6) Hz. They are also used to measure the lifetime of the metastable clock state tau=20.6+/-1.4 s, the ground state 1S0 g factor gS=-0.000,792,48(14), and the excited state 3P0 g factor gP=-0.001,976,86(21), in units of the Bohr magneton.
With the advent of optical clocks featuring fractional frequency uncertainties on the order of 10-17 and below, new applications such as chronometric leveling with few-centimeter height resolution emerge. We are developing a transportable optical clock based on a single trapped aluminum ion, which is interrogated via quantum logic spectroscopy. We employ singly charged calcium as the logic ion for sympathetic cooling, state preparation, and readout. Here, we present a simple and compact physics and laser package for manipulation of 40Ca+. Important features are a segmented multilayer trap with separate loading and probing zones, a compact titanium vacuum chamber, a near-diffraction-limited imaging system with high numerical aperture based on a single biaspheric lens, and an all-in-fiber 40Ca+ repump laser system. We present preliminary estimates of the trap-induced frequency shifts on 27Al+, derived from measurements with a single calcium ion. The micromotion-induced second-order Doppler shift for 27Al+ has been determined to be δνEMMν=-0.4-0.3 +0.4×10-18 and the black-body radiation shift is δνBBR/ν = (-4.0 ± 0.4) × 10-18. Moreover, heating rates of 30 (7) quanta per second at trap frequencies of ωrad,Ca+ ≈ 2π × 2.5 MHz (ωax,Ca+ ≈ 2π × 1.5 MHz) in radial (axial) direction have been measured, enabling interrogation times of a few hundreds of milliseconds.
With the advent of optical clocks featuring fractional frequency uncertainties on the order of 10−17 and below, new applications such as chronometric leveling with few-centimeter height resolution emerge. We are developing a transportable optical clock based on a single trapped aluminum ion, which is interrogated via quantum logic spectroscopy. We employ singly charged calcium as the logic ion for sympathetic cooling, state preparation, and readout. Here, we present a simple and compact physics and laser package for manipulation of 40Ca+. Important features are a segmented multilayer trap with separate loading and probing zones, a compact titanium vacuum chamber, a near-diffraction-limited imaging system with high numerical aperture based on a single biaspheric lens, and an all-in-fiber 40Ca+ repump laser system. We present preliminary estimates of the trap-induced frequency shifts on 27Al+, derived from measurements with a single calcium ion. The micromotion-induced second-order Doppler shift for 27Al+ has been determined to be δνEMMν=−0.4−0.3+0.4×10−18 and the black-body radiation shift is δνBBR/ν = (−4.0 ± 0.4) × 10−18. Moreover, heating rates of 30 (7) quanta per second at trap frequencies of ωrad,Ca+ ≈ 2π × 2.5 MHz (ωax,Ca+ ≈ 2π × 1.5 MHz) in radial (axial) direction have been measured, enabling interrogation times of a few hundreds of milliseconds.
Experiments were carried out using a Ca atomic beam and a tunable dye laser. Lamb dips were obtained in the fluorescence line of various Ca isotopes. It is shown that the narrow signals associated with saturation of the 4s2 1S0–4s4p 3P1, intercombination transition are potentially useful for frequency standards and highresolution spectroscopy. Measurements were made of the nuclear charge radii of six stable Ca isotopes. Radiofrequency transitions between excited state sublevels were studied. The nuclear quadrupole moment of the rarely encountered isotope 43Ca was determined.
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.