We report the 87Sr optical lattice clock developed at the National Time Service Center. We achieved a closed-loop operation of the optical lattice clock based on 87Sr atoms. The linewidth of the spin-polarized clock p...We report the 87Sr optical lattice clock developed at the National Time Service Center. We achieved a closed-loop operation of the optical lattice clock based on 87Sr atoms. The linewidth of the spin-polarized clock peak is 3.9 Hz with a clock laser pulse length of 300 ms, which corresponds to a Fourier-limited linewidth of 3 Hz. The fitting of the in-loop error signal data shows that the instability is approximately 5 × 10 15τ-1/2, affected primarily by the white noise. The fractional frequency difference averages down to 5.7 × 10 ^-17 for an averaging time of 3000 s.展开更多
We periodically modulate the lattice trapping potential of a ^(87)Sr optical clock to Floquet engineer the clock transition.In the context of atomic gases in lattices,Floquet engineering has been used to shape the dis...We periodically modulate the lattice trapping potential of a ^(87)Sr optical clock to Floquet engineer the clock transition.In the context of atomic gases in lattices,Floquet engineering has been used to shape the dispersion and topology of Bloch quasi-energy bands.Differently from these previous works manipulating the external(spatial)quasi-energies,we target the internal atomic degrees of freedom.We shape Floquet spin quasi-energies and measure their resonance profiles with Rabi spectroscopy.We provide the spectroscopic sensitivity of each band by measuring the Fisher information and show that this is not depleted by the Floquet dynamical modulation.The demonstration that the internal degrees of freedom can be selectively engineered by manipulating the external degrees of freedom inaugurates a novel device with potential applications in metrology,sensing and quantum simulations.展开更多
By using a loop mirror filter, a novel wavelength-tunable single-frequency ytterbium-doped fiber laser is developed to select single longitudinal modes in a linear cavity. The output wavelength could be tuned 2.4 nm i...By using a loop mirror filter, a novel wavelength-tunable single-frequency ytterbium-doped fiber laser is developed to select single longitudinal modes in a linear cavity. The output wavelength could be tuned 2.4 nm intervals range from 1063.3 to 1065.Tnrn with the temperature change of the fiber Bragg grating. The maximum output power could reach 32 m W while the pump power increases to 120 m W. The corresponding optical-to-optical conversion efficiency is 26.7% and the slope efficiency is 33.9%, respectively. The output power fluctuation is below 2%, and its highest signal-to-noise ratio is 60 dB.展开更多
The discovery of the momentum space crystal based on the alkaline-earth atom ^(88)Sr in narrow-line cooling has paved the way to explore this novel physical phenomenon in other cold atom systems. In this paper, a mome...The discovery of the momentum space crystal based on the alkaline-earth atom ^(88)Sr in narrow-line cooling has paved the way to explore this novel physical phenomenon in other cold atom systems. In this paper, a momentum space crystal based on the fermions ^(87)Sr in narrow-line cooling of transition^1S_0–~3P_1 is demonstrated. We theoretically analyze and compare the formation principle of the narrow-line with that of broad-line cooling, and achieve the momentum space crystal in experiment. Beyond that we present a series of numerical calculations of those important parameters which influence the distribution and size of the momentum space crystal. Correspondingly, we vary the values of these parameters in experiment to observe the momentum space crystal evolution and distribution. The experimental results are in conformity with the results of the theoretically numerical calculations. These results and analyses provide a detailed supplementary study on the formation and evolution of momentum space crystal. In addition, this work could also give a guideline on atomic manipulation by narrow-line cooling.展开更多
We present an experimental determination on the Lande g-factors for the 5 s^2 ^1 S0 and 5 s5 p ^3P0 states in ultra-cold atomic systems, which is important for evaluating the Zeeman shift of the clock transition in th...We present an experimental determination on the Lande g-factors for the 5 s^2 ^1 S0 and 5 s5 p ^3P0 states in ultra-cold atomic systems, which is important for evaluating the Zeeman shift of the clock transition in the ^87Sr optical lattice clock. The Zeeman shift of the 5 s5 p ^3 P0-5 s^2 ^1 S0 forbidden transition is measured with the π-polarized and σ^±-polarized interrogations at different magnetic field strengths. Moreover, in the g-factor measurement with the σ^±-transition spectra, it is unnecessary to calibrate the external magnetic field. By this means, the ground state 5 s^2 ^1 S0 g-factor for the ^87Sr atom is-1.306（52） ×10^-4, which is the first experimental determination to the best of our knowledge, and the result matches very well with the theoretical estimation. The differential g-factorδg between the 5 s5 p^3 P0 state and the 5 s^2 ^1 S0 state of the ^87Sr atoms is measured in the experiment as well,which are-7.67（36） ×10^-5 with π-transition spectra and-7.72（43） X 10^-5 with σ^±-transition spectra, in good agreement with the previous report [Phys. Rev. A 76（2007） 022510]. This work can also be used for determining the differential g-factor of the clock states for the optical clocks based on other atoms.展开更多
We report experiments on the observation of the ^1S0-^3P0 transition spectrum of ^88Sr in the Lamb-Dicke regime.After going through a two-stage magneto-optical trap（MOT）,88 Sr cold atoms with number of about 1 ×...We report experiments on the observation of the ^1S0-^3P0 transition spectrum of ^88Sr in the Lamb-Dicke regime.After going through a two-stage magneto-optical trap（MOT）,88 Sr cold atoms with number of about 1 × 10^5 and a longitudinal temperature of 8.4 μK are loaded into a one-dimensional（1D） optical lattice, which is realized with a semiconductor laser at 813.4 nm. Using the magnetic field-inducing ^3P1 state mixing into ^3P0 state, the spectroscopy of the1S0-3P0 transition with a linewidth of 180 Hz is detected.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474282 and 61775220)the Key Research Project of Frontier Science of the Chinese Academy of Sciences(Grant No.QYZDB-SSW-JSC004)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21030700)
文摘We report the 87Sr optical lattice clock developed at the National Time Service Center. We achieved a closed-loop operation of the optical lattice clock based on 87Sr atoms. The linewidth of the spin-polarized clock peak is 3.9 Hz with a clock laser pulse length of 300 ms, which corresponds to a Fourier-limited linewidth of 3 Hz. The fitting of the in-loop error signal data shows that the instability is approximately 5 × 10 15τ-1/2, affected primarily by the white noise. The fractional frequency difference averages down to 5.7 × 10 ^-17 for an averaging time of 3000 s.
基金Supported by the National Natural Science Foundation of China(Grant Nos.61775220,11804034,11874094,12047564,11874247,11874246)the Key Research Project of Frontier Science of the Chinese Academy of Sciences(Grant No.QYZDB-SSW-JSC004)+5 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB21030100 and XDB35010202)the Special Foundation for Theoretical Physics Research Program of China(Grant No.11647165)the Fundamental Research Funds for the Central Universities(Grant No.2020CDJQY-Z003)the National Key R&D Program of China(Grant No.2017YFA0304501),the 111 Project(Grant No.D18001)the Hundred Talent Program of the Shanxi Province(2018)the EMPIR-USOQS,EMPIR Project co-funded by the European Unions Horizon2020 Research and Innovation Programme and the EMPIR Participating States.
文摘We periodically modulate the lattice trapping potential of a ^(87)Sr optical clock to Floquet engineer the clock transition.In the context of atomic gases in lattices,Floquet engineering has been used to shape the dispersion and topology of Bloch quasi-energy bands.Differently from these previous works manipulating the external(spatial)quasi-energies,we target the internal atomic degrees of freedom.We shape Floquet spin quasi-energies and measure their resonance profiles with Rabi spectroscopy.We provide the spectroscopic sensitivity of each band by measuring the Fisher information and show that this is not depleted by the Floquet dynamical modulation.The demonstration that the internal degrees of freedom can be selectively engineered by manipulating the external degrees of freedom inaugurates a novel device with potential applications in metrology,sensing and quantum simulations.
基金Supported by the International Cooperation Projects of Ministry of Science and Technology under Grant No 2012DFB10120the National Natural Science Foundation of China under Grant No 61177059
文摘By using a loop mirror filter, a novel wavelength-tunable single-frequency ytterbium-doped fiber laser is developed to select single longitudinal modes in a linear cavity. The output wavelength could be tuned 2.4 nm intervals range from 1063.3 to 1065.Tnrn with the temperature change of the fiber Bragg grating. The maximum output power could reach 32 m W while the pump power increases to 120 m W. The corresponding optical-to-optical conversion efficiency is 26.7% and the slope efficiency is 33.9%, respectively. The output power fluctuation is below 2%, and its highest signal-to-noise ratio is 60 dB.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474282 and 61775220)the Key Research Project of Frontier Science of the Chinese Academy of Sciences(Grant No.QYZDB-SSW-JSC004)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21030100)
文摘The discovery of the momentum space crystal based on the alkaline-earth atom ^(88)Sr in narrow-line cooling has paved the way to explore this novel physical phenomenon in other cold atom systems. In this paper, a momentum space crystal based on the fermions ^(87)Sr in narrow-line cooling of transition^1S_0–~3P_1 is demonstrated. We theoretically analyze and compare the formation principle of the narrow-line with that of broad-line cooling, and achieve the momentum space crystal in experiment. Beyond that we present a series of numerical calculations of those important parameters which influence the distribution and size of the momentum space crystal. Correspondingly, we vary the values of these parameters in experiment to observe the momentum space crystal evolution and distribution. The experimental results are in conformity with the results of the theoretically numerical calculations. These results and analyses provide a detailed supplementary study on the formation and evolution of momentum space crystal. In addition, this work could also give a guideline on atomic manipulation by narrow-line cooling.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61127901,11404025 and 91536106the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDB21030700+1 种基金the Key Research Project of Frontier Science of Chinese Academy of Sciences under Grant No QYZDB-SSW-JSC004the China Postdoctoral Science Foundation under Grant No 2014M560061
文摘We present an experimental determination on the Lande g-factors for the 5 s^2 ^1 S0 and 5 s5 p ^3P0 states in ultra-cold atomic systems, which is important for evaluating the Zeeman shift of the clock transition in the ^87Sr optical lattice clock. The Zeeman shift of the 5 s5 p ^3 P0-5 s^2 ^1 S0 forbidden transition is measured with the π-polarized and σ^±-polarized interrogations at different magnetic field strengths. Moreover, in the g-factor measurement with the σ^±-transition spectra, it is unnecessary to calibrate the external magnetic field. By this means, the ground state 5 s^2 ^1 S0 g-factor for the ^87Sr atom is-1.306（52） ×10^-4, which is the first experimental determination to the best of our knowledge, and the result matches very well with the theoretical estimation. The differential g-factorδg between the 5 s5 p^3 P0 state and the 5 s^2 ^1 S0 state of the ^87Sr atoms is measured in the experiment as well,which are-7.67（36） ×10^-5 with π-transition spectra and-7.72（43） X 10^-5 with σ^±-transition spectra, in good agreement with the previous report [Phys. Rev. A 76（2007） 022510]. This work can also be used for determining the differential g-factor of the clock states for the optical clocks based on other atoms.
基金supported by the National Nature Science Foundation of China (Nos. 61127901 and 11474282)the Key Project of the Chinese Academy of Sciences (No. KJZD-EW-W02)
文摘We report experiments on the observation of the ^1S0-^3P0 transition spectrum of ^88Sr in the Lamb-Dicke regime.After going through a two-stage magneto-optical trap（MOT）,88 Sr cold atoms with number of about 1 × 10^5 and a longitudinal temperature of 8.4 μK are loaded into a one-dimensional（1D） optical lattice, which is realized with a semiconductor laser at 813.4 nm. Using the magnetic field-inducing ^3P1 state mixing into ^3P0 state, the spectroscopy of the1S0-3P0 transition with a linewidth of 180 Hz is detected.
