Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Chinese Physics Letters

State Preparation in a Cold Atom Clock by Optical Pumping

Yu-Xiong Duan, Bin Wang, Jingfeng Xiang, Qian Liu, Qiuzhi Qu, Desheng Lü, Liang Liu

Published Jul 1, 2017• 7 citations
Publisher

Abstract

We implement optical pumping to prepare cold atoms in our prototype of the 87 Rb space cold atom clock, which operates in the one-way mode. Several modifications are made on our previous physical and optical system. The effective atomic signal in the top detection zone is increased to 2.5 times with 87% pumping efficiency. The temperature of the cold atom cloud is increased by 1.4 μK. We study the dependences of the effective signal gain and pumping efficiency on the pumping laser intensity and detuning. The effects of σ transition are discussed. This technique may be used in the future space cold atom clocks.

DOI
10.1088/0256-307x/34/7/073201

Related papers

Improvement of the short-term stability of atomic fountain clock with state preparation by two-laser optical pumping*

Lei Han, Fang Fang, Weiliang Chen +4 more

To improve the signal to noise ratio (SNR) and the short-term stability of cesium atomic fountain clocks, the work of two-laser optical pumping is presented theoretically and experimentally. The short-term stability of the NIM6 fountain clock has been improved by preparing more cold atoms in the | F = 4, mF = 0〉 clock state with a shortened cycle time. Two π-polarized laser beams overlapped in the horizontal plane have been applied after launching, one is resonant with | F = 4〉 → | F′ = 4〉 transition and the other is resonant with | F = 3〉 → | F′ = 4〉 transition. With optical pumping, the population accumulated in the | mF = 0〉 clock state is improved from 11% to 63%, and the detection signal is increased by a factor of 4.2, the SNR of the clock transition probability and the short-term stability are also improved accordingly.

Chinese Physics B•Feb 2, 2021•4 citations

An effective pumping method for increasing atomic utilization in a compact cold atom clock*

Xinchuan Ouyang, Bowen Yang, Jianliao Deng +5 more

We propose a simple pumping method to increase the effective population of cold atoms in the clock state and investigate the factors which affect the pumping efficiency in cold atom systems. We report the theory and demonstrate the corresponding experiment in an 87Rb integrating sphere cold atom clock. The experimental results show that the population of cold atoms in the Zeeman sublevel |F = 2, mF = 0〉 is approximately 1.62 times that of the result using optical pumping alone. This method can also be applied to increase the effective population in any one of the target Zeeman sublevels in other cold atom systems.

Chinese Physics B•Apr 29, 2021•2 citations

Combined quantum-state preparation and laser cooling of a continuous beam of cold atoms

Gianni Di Domenico, Laurent Devenoges, Claire Dumas +1 more

We use two-laser optical pumping on a continuous atomic fountain in order to prepare cold cesium atoms in the same quantum ground state. A first laser excites the $F=4$ ground state to pump the atoms toward $F=3$ while a second $\ensuremath{\pi}$-polarized laser excites the $F=3\ensuremath{\rightarrow}{F}^{'}=3$ transition of the ${D}_{2}$ line to produce Zeeman pumping toward $m=0$. To avoid trap states, we implement the first laser in a two-dimensional optical lattice geometry, thereby creating polarization gradients. This configuration has the advantage of simultaneously producing Sisyphus cooling when the optical lattice laser is tuned between the $F=4\ensuremath{\rightarrow}{F}^{'}=4$ and $F=4\ensuremath{\rightarrow}{F}^{'}=5$ transitions of the ${D}_{2}$ line, which is important to remove the heat produced by optical pumping. Detuning the frequency of the second $\ensuremath{\pi}$-polarized laser reveals the action of a mechanism improving both laser cooling and state-preparation efficiency. A physical interpretation of this mechanism is discussed.

arXiv:1009.1358•Physical Review A•Nov 29, 2010•20 citations

Laser Cooling of 87 Rb to 1.5 μK in a Fountain Clock

Bin Wang, Desheng Lü, Qiuzhi Qu +4 more

We report an experiment on the adiabatic cooling of 87 Rb atoms in an atomic fountain to a temperature as low as 1.5 μK, which is roughly twice the recoil temperature. The atomic fountain has the (1,1,1) optical geometry for cooling and launching of cold atoms. The atoms are first cooled in an optical molasses of 6 beams to 3.4 μK by polarization gradient geometry and then are adiabatically cooled by decreasing the intensity of laser from 1.8I s per beam to zero in 1 ms during the launching of cold atoms. We also study the dependences of atomic temperature on different laser parameters. The method we used is useful in any cold atom physics experiment.

Chinese Physics Letters•Jun 1, 2011•17 citations

Laser-pumped and laser-cooled atomic clocks for space applications

Walter F. Buell

Highly stable atomic frequency standards are of increasing importance for a variety of space applications, ranging from communication to navigation and time transfer to tests of fundamental science. We present a discussion of the improvements possible with laser pumping of vapor cell clocks, including applying coherent population trapping (CPT) techniques. We also present our progress toward a cold atom clock based on magneto-optically trapped atoms for space applications.

Laser and Particle Beams•Dec 1, 1998•9 citations

Accumulation of a clock state population by optical pumping in a caesium fountain

S.E. Park, K. Szymaniec

We have implemented a technique of optical pumping (OP) to increase the clock state populations in a caesium fountain frequency standard. Our initial experiments have demonstrated accumulation of 75% of the atoms in the mF= 0 sublevel (clock state), which can be compared to a typical 11% population of this sublevel with no additional OP applied. As the (OP) process requires scattering of some 20 photons per atom, the atomic cloud is heated by nearly 1 μK and the final number of atoms reaching the detector is reduced by up to a factor of two, depending on the molasses temperature. Using the OP technique in the NPL-CsF2 fountain we have observed a four-fold net increase of the clock state population.

•Jun 1, 2010•3 citations
We implement optical pumping to prepare cold atoms in our prototype of the 87 Rb space cold atom clock, which operates in the one-way mode. Several modifications are made on our previous physical and optical system. The effective atomic signal in the top detection zone is increased to 2.5 times with 87% pumping efficiency. The temperature of the cold atom cloud is increased by 1.4 μK. We study the dependences of the effective signal gain and pumping efficiency on the pumping laser intensity and detuning. The effects of σ transition are discussed. This technique may be used in the future space cold atom clocks.
To improve the signal to noise ratio (SNR) and the short-term stability of cesium atomic fountain clocks, the work of two-laser optical pumping is presented theoretically and experimentally. The short-term stability of the NIM6 fountain clock has been improved by preparing more cold atoms in the | F = 4, mF = 0〉 clock state with a shortened cycle time. Two π-polarized laser beams overlapped in the horizontal plane have been applied after launching, one is resonant with | F = 4〉 → | F′ = 4〉 transition and the other is resonant with | F = 3〉 → | F′ = 4〉 transition. With optical pumping, the population accumulated in the | mF = 0〉 clock state is improved from 11% to 63%, and the detection signal is increased by a factor of 4.2, the SNR of the clock transition probability and the short-term stability are also improved accordingly.
We propose a simple pumping method to increase the effective population of cold atoms in the clock state and investigate the factors which affect the pumping efficiency in cold atom systems. We report the theory and demonstrate the corresponding experiment in an 87Rb integrating sphere cold atom clock. The experimental results show that the population of cold atoms in the Zeeman sublevel |F = 2, mF = 0〉 is approximately 1.62 times that of the result using optical pumping alone. This method can also be applied to increase the effective population in any one of the target Zeeman sublevels in other cold atom systems.
We use two-laser optical pumping on a continuous atomic fountain in order to prepare cold cesium atoms in the same quantum ground state. A first laser excites the F=4F=4F=4 ground state to pump the atoms toward F=3F=3F=3 while a second $\ensuremath{\pi}$-polarized laser excites the $F=3\ensuremath{\rightarrow}{F}^{'}=3$ transition of the D2{D}_{2}D2​ line to produce Zeeman pumping toward m=0m=0m=0. To avoid trap states, we implement the first laser in a two-dimensional optical lattice geometry, thereby creating polarization gradients. This configuration has the advantage of simultaneously producing Sisyphus cooling when the optical lattice laser is tuned between the $F=4\ensuremath{\rightarrow}{F}^{'}=4$ and $F=4\ensuremath{\rightarrow}{F}^{'}=5$ transitions of the D2{D}_{2}D2​ line, which is important to remove the heat produced by optical pumping. Detuning the frequency of the second $\ensuremath{\pi}$-polarized laser reveals the action of a mechanism improving both laser cooling and state-preparation efficiency. A physical interpretation of this mechanism is discussed.
We report an experiment on the adiabatic cooling of 87 Rb atoms in an atomic fountain to a temperature as low as 1.5 μK, which is roughly twice the recoil temperature. The atomic fountain has the (1,1,1) optical geometry for cooling and launching of cold atoms. The atoms are first cooled in an optical molasses of 6 beams to 3.4 μK by polarization gradient geometry and then are adiabatically cooled by decreasing the intensity of laser from 1.8I s per beam to zero in 1 ms during the launching of cold atoms. We also study the dependences of atomic temperature on different laser parameters. The method we used is useful in any cold atom physics experiment.
We have implemented a technique of optical pumping (OP) to increase the clock state populations in a caesium fountain frequency standard. Our initial experiments have demonstrated accumulation of 75% of the atoms in the mF= 0 sublevel (clock state), which can be compared to a typical 11% population of this sublevel with no additional OP applied. As the (OP) process requires scattering of some 20 photons per atom, the atomic cloud is heated by nearly 1 μK and the final number of atoms reaching the detector is reduced by up to a factor of two, depending on the molasses temperature. Using the OP technique in the NPL-CsF2 fountain we have observed a four-fold net increase of the clock state population.