Secular Motion Frequencies of 9Be+ Ions and 40Ca+ Ions in Bi-component Coulomb Crystals*

Li, Haixia; Li, Min; Zhang, Qian-Yu; Tong, Xin

doi:10.1088/0256-307x/36/7/073701

Cited by 7 publications

(4 citation statements)

References 26 publications

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“…The 40 Ca + ions are firstly loaded into the ion trap by photoionizing the neutral atoms from a Ca oven. [20] The laser cooling of the 40 Ca + ions is achieved by a cooling laser of 397 nm on the transition of 4s 2 S 1/2 ↔ 4p 2 P 1/2 and a repumping laser of 866 nm on the transition of 3d 2 D 3/2 ↔ 4p 2 P 1/2 as illustrated in Fig. 2(a).…”

Section: Methodsmentioning

confidence: 99%

Investigation of spatial structure and sympathetic cooling in the ⁹Be⁺–⁴⁰Ca⁺ bi-component Coulomb crystals

Zhang

et al. 2023

Chinese Phys. B

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We study the spatial structure and sympathetic cooling of the bi-component Coulomb crystal (CC) which consists of approximate 450 9Be+ ions and 450 40Ca+ ions with a mass ratio of 0.225 in a segmented linear ion trap. By two-dimensional imaging of the bi-component CC, the 9Be+ ions are found to be surrounded by the 40Ca+ ions in the radial direction with a separation ratio of ~2.0, and the axial length of the 9Be+ ions occupied area is much larger than that of the 40Ca+ ions occupied area. Combined with the previous experimental results, the structure of the 9Be+-40Ca+ CC shows the larger the difference in the mass-charge ratio, the larger the separation between the two species. The comparison of the fluorescence spectra of the 9Be+ ions in the bi-component CC and the pure CC indicates that the 9Be+ ions can be sympathetically cooled and stably localized by the laser-cooled 40Ca+ ions during the recording of the fluorescence spectrum.

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Section: Methodsmentioning

confidence: 99%

Investigation of spatial structure and sympathetic cooling in the ⁹Be⁺–⁴⁰Ca⁺ bi-component Coulomb crystals

Zhang

et al. 2023

Chinese Phys. B

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“…多组分库仑晶体往往采用协同冷却的方式, 由于经常选取相对质量相差较大的离子, 因而具有明显的分层现象, 如 24 Mg + , 40 Ca + 等. 也有选取较高电荷数离子的双组份晶体, 如Ho 14+ 和Be + , 其排布方式与离子的荷质比和空间电荷效应相关 [14,15] . 另外, 调控离子阱参数可以精密控制库仑晶体, 减小附加微运动等 [12,16,17] .…”

Section: 库仑晶体的研究和应用前景十分广泛在非线性动力学方面库仑晶体中存在着粒子的混沌行unclassified

Simulation of Coulomb crystal structure and motion trajectory of calcium ions in linear ion trap

Zhang¹,

Zhou²,

Shen³

et al. 2023

Acta Phys. Sin.

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Coulomb crystal yields a wide range of applications including quantum computing and simulation, phase transitions, quantum logic spectroscopy, nonlinear dynamics and chaos, chemical reaction process, etc. The structure of the Coulomb crystal and the trajectory of each trapped ion are typically determined by the parameters of the trap and the ion species. However, dark ions are often inevitable in experiments, which introduces uncertainty to the desired crystal structures and ion trajectories. Few research has been conducted to investigate the configuration change of the crystal in the presence of dark ions and the influence of a dark ion on its surrounding ion trajectories in a multi-ion system. In this paper, we utilize the molecular dynamics simulation software LAMMPS and the (py) Lion package (modified to adapt the semi-classical theory of laser cooling) for the simulation of the 3D ion trajectories of Coulomb crystals. The formation process of 40Ca+Coulomb crystals in a linear trap is simulated. With the micromotion and secular motion trajectories of each ion, we calculate the temperature of Coulomb crystal and the average velocity of specific ions. It’s observed that the crystal structure exhibits obvious layering phenomenon when the trapped ions yield a large difference in their charge-to-mass ratio (CMR), however, layering is not obvious with a small difference in the CMR. In addition, we simulate and compare the Coulomb crystal structure formed by pure 40Ca+ ions and that formed by 40Ca+ ions mixed with a small number of dark ions including isotopic ions (44Ca+) and impurity ions (CaH+). Three different cases are investigated, namely the 1D ion string, 2D plane structure and 3D helical structure. Results show that ions in the neighborhood of a dark ion exhibit around micron-order position changes compared to their positions before the dark ion is formed. Such a change can be measured in experiment through microscopic imaging, providing a way to identify dark ions in Column crystals with a large number of ions.

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“…From the simulation model, we can calculate the dipole trap force is on the order of 10 −18 -10 −17 N, which is a level larger than the residual force that is the prerequisite for the all-optical trapping of a single 40 Ca + . The segmented structure is beneficial to precisely control the position of a single ion or even a string of ions, [20][21][22][23] and the comparatively short length and wide pole distance are essential to align the dipole beam with the trap center for the Gaussian shape of the highpower laser, which is also helpful for increasing the numerical aperture of the imaging system. The whole trap is enclosed in a vacuum chamber with a background gas pressure of ∼ 5 × 10 −9 Pa.…”

Section: Ion Trap Systemmentioning

confidence: 99%

Setup of a dipole trap for all-optical trapping*

Wang¹,

Chen²,

Huang³

et al. 2021

Chinese Phys. B

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Micromotion induced by the radio-frequency field contributes greatly to the systematic frequency shifts of optical frequency standards. Although different strategies for mitigating this effect have been proposed, trapping ions optically has the potential to provide a generic solution to the elimination of micromotion. This could be achieved by trapping a single ion in the dipole trap composed of a highpower laser field. Here, we present the setup of the dipole trap composed of a 532 nm laser at a power of 10 W aiming to optically trap a single 40Ca+ and we observe an AC-Stark shift of the fluorescence spectrum line of ∼22 MHz caused by the 532 nm dipole beam. The beam waist of the dipole laser is several microns, which would provide a dipole potential strong enough for all-optical trapping of a single 40Ca+ ion.

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Secular Motion Frequencies of ⁹Be⁺ Ions and ⁴⁰Ca⁺ Ions in Bi-component Coulomb Crystals*

Cited by 7 publications

References 26 publications

Investigation of spatial structure and sympathetic cooling in the ⁹Be⁺–⁴⁰Ca⁺ bi-component Coulomb crystals

Investigation of spatial structure and sympathetic cooling in the ⁹Be⁺–⁴⁰Ca⁺ bi-component Coulomb crystals

Simulation of Coulomb crystal structure and motion trajectory of calcium ions in linear ion trap

Setup of a dipole trap for all-optical trapping*

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Secular Motion Frequencies of 9Be+ Ions and 40Ca+ Ions in Bi-component Coulomb Crystals*

Cited by 7 publications

References 26 publications

Investigation of spatial structure and sympathetic cooling in the 9Be+–40Ca+ bi-component Coulomb crystals

Investigation of spatial structure and sympathetic cooling in the 9Be+–40Ca+ bi-component Coulomb crystals

Simulation of Coulomb crystal structure and motion trajectory of calcium ions in linear ion trap

Setup of a dipole trap for all-optical trapping*

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Secular Motion Frequencies of ⁹Be⁺ Ions and ⁴⁰Ca⁺ Ions in Bi-component Coulomb Crystals*

Investigation of spatial structure and sympathetic cooling in the ⁹Be⁺–⁴⁰Ca⁺ bi-component Coulomb crystals

Investigation of spatial structure and sympathetic cooling in the ⁹Be⁺–⁴⁰Ca⁺ bi-component Coulomb crystals