Determining the structural phase transition point from the temperature of ~（40）Ca~＋ Coulomb crystal

We observed the linear-to-zigzag structural phase transition of a ^40Ca^＋ crystal in a homemade linear Paul trap. The values of the total temperature of the ion crystals during the phase transition are derived using the molecular-dynamics（MD） simulation method. A series of simulations revealed that the ratio of the radial to axial secular frequencies has a dependence on the total temperature that obeys different functional forms for linear and zigzag structures, and the transition point occurs where these functions intersect; thus, the critical value of the ratio of secular frequencies that drives the structure phase transition can be derived.     

离子光频标的原理和发展

人类对时间的计量历史可以追溯到几千年前,随着科学技术的发展与进步,人类对事件的计量精度也越来越精确。当前,世界上最精确的计时工具为光频标,可以达到百亿年不差一秒的水平。文章回顾了离子光频标的发展过程和当前的研究进展,简要介绍了钙离子光频标和量子逻辑铝离子光频标的原理及进展。     

Deceleration of Metastable Li~+ Beam by Combining Electrostatic Lens and Ion Trap Technique

Ion deceleration has played a critical role in ion-related research when the ions are produced in the form of a high-energy beam.We present a deceleration method combining electrostatic lens and ion trap technique,which can effectively decelerate ions to energy below the trapping potential of a typical ion trap.The experiments were performed on metastable 1s2s³S₁Li⁺ ions,and demonstrated that the kinetic energy could easily be reduced from ～450 e V to a few e V,w...     

金刚石簿膜淀积过程中微波等离子体特性

一、引言 在金刚石薄膜的制备过程中,人们往往监测成膜过程中的宏观参量,使其工艺的重复性,优选性受到了很大限制。而随着对膜质量和结构的要求越来越高,人们开始开展对低压下合成金刚石机理的研究,但至今未见系统地研究宏观参量与等离子体参量方面的工作报道。     

Optimization of endcap trap for single-ion manipulation

Potential distribution is an important characteristic for evaluating the performance of an ion trap. Here, we analyze and optimize the potential distribution of an endcap ion trap for single-ion trapping.We obtain an optimal endcap radius of225 μm–250 μm, endcap-shield gap of ～ 250 μm, and inter-endcap distance of 540 μm–590 μm. The simulation method for analysis can also be applied to other ion traps, which is useful for improving the design and assembly of ion traps.     

Significantly Improving the Escape Time of a Single ~(40)Ca~+ Ion in a Linear Paul Trap by Fast Switching of the Endcap Voltage

Sympathetic cooling is a method used to lower the kinetic energy of ions with complicated energy-level structures,via Coulomb interactions with laser-cooled ions in an ion trap.The ion to be sympathetically cooled is sometimes prepared outside of the trap,and it is critical to introduce this ion into the trap by temporarily lowering the potential of one endcap without allowing the coolant ion to escape.We study the time required for a laser-cooled ion to escape from a linear Paul trap when the v...     

Experimental Improvement of Signal of a Single Laser-Cooled Trapped ^40Ca^＋ Ion

A single ^40Ca^＋ ion is loaded in a miniature Paul trap and the probability of directly loading a single ion is above 50%. The signal-to-noise ratio and the storage time for a single ion have been improved by minimizing the ion micromotion and locking a 397nm cooling laser to a Fabry-Perot interferometer and optogalvanic signal. From the fluorescence spectrum, the ion temperature is estimated to be about 5mK.     

化学气相淀积中甲烷含量变化的等离子体参数诊断

一、引言 金刚石薄膜以其优异的特性越来越受到人们的重视。人们已用各种方法制备出金刚石薄膜、并详细研究了膜质量、膜的形貌与各种宏观参量的关系。在这里,含碳物源相对于氢气的浓度比对金刚石膜的结构和形貌的影响是相当严重的。从许多报道中可知,当     

两种互补性的核磁共振实验验证

玻尔互补性[1,2]通常能表述为任何量子体系至少有两种不能同时被观察的客观性质.     

Paul阱中基态低能多离化Fen+(n=1-3)离子的存储及反应特性

利用垂直交叉的激光束在Paul阱中溅射固体铸铁(FeC)靶,产生了低能多电荷铁离子Fen+(n=1-3),得到了Fe3+离子在本底气压为3.0×10-7Pa下的衰减速率(0.96s-1)以及在1.3×10-5Pa下和中性气体分子N2的反应产物.