The 27Al＋ ion optical clock is one of the most attractive optical clocks due to its own advantages such as low black-body radiation shift at room temperature and insensitivity to the magnetic drift. However, it canno...The 27Al＋ ion optical clock is one of the most attractive optical clocks due to its own advantages such as low black-body radiation shift at room temperature and insensitivity to the magnetic drift. However, it cannot be laser-cooled directly in the absence of 167nm laser to date. This problem can be solved by sympathetic cooling. In this work, a linear Paul trap is used to trap both 40Ca＋ and 27A1＋ ions simultaneously, and a single Dopplercooled 40Ca＋ ion is employed to sympathetically cool a single 27A1＋ ion. Thus a ＇bright-dark＇ two-ion crystal has been successfully synthesized. The temperature of the crystal has been estimated to be about 7mK by measuring the ratio of carrier and sideband spectral intensities. Finally, the dark ion is proved to be an 27Al＋ ion by precise measuring of the ion crystal＇s secular motion frequency, which means that it is a great step for our 2Z Al＋ quantum logic clock.展开更多
The 7Li＋ ion is one of the most important candidates for verifying QED theory and obtaining the precise value of the fine-structure constant ~. However, direct laser cooling of trapped Li＋ ions will lead to strong b...The 7Li＋ ion is one of the most important candidates for verifying QED theory and obtaining the precise value of the fine-structure constant ~. However, direct laser cooling of trapped Li＋ ions will lead to strong background fluorescence which will influence the spectrum detection. The sympathetic cooling technique is a good choice to solve the problem. In this work, we report sympathetic cooling of 7 Li＋ ions to few mK using 40Ca＋ ions in a linear Paul trap. A mixed ion crystal of 40Ca＋ ions and 7Li＋ ions are obtained. We also analyze the motion frequency spectra of pure 40 Ca＋ ions and mixed ions.展开更多
基金Supported by the National High Technology Research and Development Program of China under Grant No 2012AA120701the National Natural Science Foundation of China under Grant No 11174326
文摘The 27Al＋ ion optical clock is one of the most attractive optical clocks due to its own advantages such as low black-body radiation shift at room temperature and insensitivity to the magnetic drift. However, it cannot be laser-cooled directly in the absence of 167nm laser to date. This problem can be solved by sympathetic cooling. In this work, a linear Paul trap is used to trap both 40Ca＋ and 27A1＋ ions simultaneously, and a single Dopplercooled 40Ca＋ ion is employed to sympathetically cool a single 27A1＋ ion. Thus a ＇bright-dark＇ two-ion crystal has been successfully synthesized. The temperature of the crystal has been estimated to be about 7mK by measuring the ratio of carrier and sideband spectral intensities. Finally, the dark ion is proved to be an 27Al＋ ion by precise measuring of the ion crystal＇s secular motion frequency, which means that it is a great step for our 2Z Al＋ quantum logic clock.
基金Supported by the National Basic Research Program of China under Grant No 2010CB832803the National Natural Science Foundation of China under Grant Nos 11004222 and 91121016the Chinese Academy of Sciences
文摘The 7Li＋ ion is one of the most important candidates for verifying QED theory and obtaining the precise value of the fine-structure constant ~. However, direct laser cooling of trapped Li＋ ions will lead to strong background fluorescence which will influence the spectrum detection. The sympathetic cooling technique is a good choice to solve the problem. In this work, we report sympathetic cooling of 7 Li＋ ions to few mK using 40Ca＋ ions in a linear Paul trap. A mixed ion crystal of 40Ca＋ ions and 7Li＋ ions are obtained. We also analyze the motion frequency spectra of pure 40 Ca＋ ions and mixed ions.
