We report a clock transition spectrum approach,which is used to calibrate the zero-crossing temperature and frequency drift of an ultralow expansion(ULE)cavity with a Hertz level resolution.With this approach,the line...We report a clock transition spectrum approach,which is used to calibrate the zero-crossing temperature and frequency drift of an ultralow expansion(ULE)cavity with a Hertz level resolution.With this approach,the linear and nonlinear drifts of the ULE cavity along a variety of controlled temperatures are clearly presented.When the controlled temperature of ULE cavity is tuned away from the zero-crossing temperature of the ULE cavity,the cavity shows larger and larger nonlinear drift.According to our theoretical analysis and experimental results,we investigate more details of the drift property of the ULE cavity around the zero-crossing temperature,which has seldom been explored before.We can definitely conclude that the zero-crossing temperature of our ULE cavity used in an ytterbium(Yb)lattice clock is around 31.7℃.展开更多
Magic wavelengths for laser trapping of barium atoms in the optical clock transition at l107nm between the 6s2 1So state optical lattices are calculated with considering the and 6s5d 3D1 state. Theoretical calculation...Magic wavelengths for laser trapping of barium atoms in the optical clock transition at l107nm between the 6s2 1So state optical lattices are calculated with considering the and 6s5d 3D1 state. Theoretical calculation shows that there are several magic wavelengths with the linearly polarized trapping laser. The trap depths of the optical lattice and the slope of light shift difference with different magic wavelengths are also calculated, Some of these magic wavelengths are selected and recommended as potentially suitable magic wavelengths for the optical lattice trapping laser.展开更多
Ac-Stark shift of atom levels is caused by an ac-electromagnetic field. As an electromagnetic wave, laser light does induce ac-Stark shift. It is proved experimentally that if the light is linearly polarized, the dyna...Ac-Stark shift of atom levels is caused by an ac-electromagnetic field. As an electromagnetic wave, laser light does induce ac-Stark shift. It is proved experimentally that if the light is linearly polarized, the dynamic polarizability changes with polarization direction. The polarization direction of the linearly-polarized laser is tuned by 720°, and the ac-Stark shifts of the 4S1/2,m=±1/2→3D5/2,m=±1/2 clock transitions in ^40Ca^＋ are measured in steps of 10°. The frequency shifts change with laser polarization in a periodical manner and have values opposite to each other.展开更多
We report on the observation of the highly forbidden ^1S0–^3P0 optical clock transition in laser-cooled ^199Hg atoms.More than 95% depletion of cold ^199Hg atoms is detected in the magneto-optical trap. Using the fre...We report on the observation of the highly forbidden ^1S0–^3P0 optical clock transition in laser-cooled ^199Hg atoms.More than 95% depletion of cold ^199Hg atoms is detected in the magneto-optical trap. Using the free-of-field detection method, the AC Stark shift from the cooling laser is removed from the in-field spectroscopy. At low-power clock laser pumping, the linewidth of the clock spectroscopy is approximately 450 k Hz（full width at half-maximum）, which corresponds to a Doppler broadening at the atom temperature of 60 μK. We determine the -1S0–^13P0transition frequency to be 1,128,575,290.819（14） MHz by referencing with a hydrogen maser and measuring with a fiber optical frequency comb. Moreover, a weak Doppler-free signal is observed.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61227805,11574352,91536104,and 91636215)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21030100)
文摘We report a clock transition spectrum approach,which is used to calibrate the zero-crossing temperature and frequency drift of an ultralow expansion(ULE)cavity with a Hertz level resolution.With this approach,the linear and nonlinear drifts of the ULE cavity along a variety of controlled temperatures are clearly presented.When the controlled temperature of ULE cavity is tuned away from the zero-crossing temperature of the ULE cavity,the cavity shows larger and larger nonlinear drift.According to our theoretical analysis and experimental results,we investigate more details of the drift property of the ULE cavity around the zero-crossing temperature,which has seldom been explored before.We can definitely conclude that the zero-crossing temperature of our ULE cavity used in an ytterbium(Yb)lattice clock is around 31.7℃.
基金Supported by the Scientific Research Program Funded by Shaanxi Provincial Education Department under Grant No 14JK1402
文摘Magic wavelengths for laser trapping of barium atoms in the optical clock transition at l107nm between the 6s2 1So state optical lattices are calculated with considering the and 6s5d 3D1 state. Theoretical calculation shows that there are several magic wavelengths with the linearly polarized trapping laser. The trap depths of the optical lattice and the slope of light shift difference with different magic wavelengths are also calculated, Some of these magic wavelengths are selected and recommended as potentially suitable magic wavelengths for the optical lattice trapping laser.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.91336211,11634013,11622434,11474318,and 11504094)the Chinese Academy of Sciences(Grant No.XDB21030000)
文摘Ac-Stark shift of atom levels is caused by an ac-electromagnetic field. As an electromagnetic wave, laser light does induce ac-Stark shift. It is proved experimentally that if the light is linearly polarized, the dynamic polarizability changes with polarization direction. The polarization direction of the linearly-polarized laser is tuned by 720°, and the ac-Stark shifts of the 4S1/2,m=±1/2→3D5/2,m=±1/2 clock transitions in ^40Ca^＋ are measured in steps of 10°. The frequency shifts change with laser polarization in a periodical manner and have values opposite to each other.
基金supported by the National Natural Science Foundation of China(NSFC)(No.91436105)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB21030200)
文摘We report on the observation of the highly forbidden ^1S0–^3P0 optical clock transition in laser-cooled ^199Hg atoms.More than 95% depletion of cold ^199Hg atoms is detected in the magneto-optical trap. Using the free-of-field detection method, the AC Stark shift from the cooling laser is removed from the in-field spectroscopy. At low-power clock laser pumping, the linewidth of the clock spectroscopy is approximately 450 k Hz（full width at half-maximum）, which corresponds to a Doppler broadening at the atom temperature of 60 μK. We determine the -1S0–^13P0transition frequency to be 1,128,575,290.819（14） MHz by referencing with a hydrogen maser and measuring with a fiber optical frequency comb. Moreover, a weak Doppler-free signal is observed.
