We present an experimental demonstration of the rotation measurement using a compact cold atom gyroscope. Atom interference fringes are observed in the stationary frame and the rotating frame, respectively. The phase ...We present an experimental demonstration of the rotation measurement using a compact cold atom gyroscope. Atom interference fringes are observed in the stationary frame and the rotating frame, respectively. The phase shift and contrast of the interference fringe are experimentally investigated. The results show that the contrast of the interference fringe is well held when the platform is rotated, and the phase shift of the interference fringe is linearly proportional to the rotation rate of the platform. The long-term stability, which is evaluated by the overlapped Allan deviation, is 8.5 × 10^-6 rad/s over the integrating time of 1000s.展开更多
A miniaturized atomic spin-exchange relaxation-free(SERF)co-magnetometer measures angular velocity using a balanced polarimetry technique which is easily affected by the laser power.A laser power closed-loop control s...A miniaturized atomic spin-exchange relaxation-free(SERF)co-magnetometer measures angular velocity using a balanced polarimetry technique which is easily affected by the laser power.A laser power closed-loop control system is usually used to suppress the fluctuation of the laser power.Although this method can greatly eliminate the fluctuation of the in-loop laser power(the feedback laser),it cannot fully eliminate the fluctuation of the out-of-loop laser power(the signal measurement laser).This leads to SERF gyroscope laser power error,which reduces the inertial measurement accuracy.In this paper,the influence mechanism of the split ratio(the ratio of the in-loop laser power to the out-of-loop laser power)on the out-of-loop laser power control accuracy is analyzed by establishing a laser power transmission model inside and outside the loop.Moreover,a method is developed to improve the out-of-loop laser power stability by optimizing the split ratio.Comparative experiments showed that the relative Allan standard deviation of the out-of-loop laser power decreased from 5.48×10^(-6)to 2.62×10^(-6)at 100 s,and decreased by an order of magnitude from 1.76×10^(-5)to 3.30×10^(-6)at1000 s.Correspondingly,the rate ramp coefficient in the Allan standard deviation curve of the SERF gyroscope test data decreased from 1.312[(°/h)/h]to 0.246[(°/h)/h].And the bias stability increased from 0.032°/h to 0.019°/h.Therefore,the proposed method can improve the long-term stability of the probe laser power and effectively suppress the laser power error of the SERF gyroscope.展开更多
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 th...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,m_(F)=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|m_(F)=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.展开更多
We propose a robust scheme that creates a toroidal magnetic potential on a single-layer atom chip. The wire layout consists of two interleaved Archimedean spirals, which avoids the trapping perturbation caused by the ...We propose a robust scheme that creates a toroidal magnetic potential on a single-layer atom chip. The wire layout consists of two interleaved Archimedean spirals, which avoids the trapping perturbation caused by the input and output ports. By using a rotation bias field, the minimum of the time-averaged orbiting potential is lifted from zero, and then a relatively smooth and harmonic ring trap is formed. The location of the waveguide is immune to the magnetic variations, as it is only determined by the wire layout. The ring waveguide offers an ideal solution to developing a compact and portable atomic Kyroscope.展开更多
Atomic spin gyroscope (ASG) based on comagnetometer is a high sensitive and compact gyroscope for future inertial navigation applications. The start-up time was several hours of the demonstrated ASGs based on 3He-K or...Atomic spin gyroscope (ASG) based on comagnetometer is a high sensitive and compact gyroscope for future inertial navigation applications. The start-up time was several hours of the demonstrated ASGs based on 3He-K or21 Ne-Rb-K comagnetometer, and only a few inertial navigation applications allow such a long time for preparation. We report the demonstration of an ASG based on 129Xe-Cs comagnetometer, which decreases the start-up time to 10 minutes and decreases the operation temperature by 40% as well. By operating this ASG in spin exchange relaxation free regime, a sensitivity of 7×10 -5 °/(s Hz1/2) was achieved.展开更多
The electronic structure and magnetic properties of the transition-metal （TM） atoms （Sc-Zn, Pt and Au） doped zigzag GaN single-walled nanotubes （NTs） are investigated using first-principles spin-polarized densit...The electronic structure and magnetic properties of the transition-metal （TM） atoms （Sc-Zn, Pt and Au） doped zigzag GaN single-walled nanotubes （NTs） are investigated using first-principles spin-polarized density functional calculations. Our results show that the bindings of all TM atoms are stable with the binding energy in the range of 6-16 eV. The Sc- and V-doped GaN NTs exhibit a nonmagnetic behavior. The GaN NTs doped with Ti, Mn, Ni, Cu and Pt are antiferromagnetic. On the contrary, the Cr-, Fe-, Co-, Zn- and Au-doped GaN NTs show the ferromagnetic characteristics. The Mn- and Co- doped GaN NTs induce the largest local moment of 4#B among these TM atoms. The local magnetic moment is dominated by the contribution from the substitutional TM atom and the N atoms bonded with it.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11227083 and 91536221
文摘We present an experimental demonstration of the rotation measurement using a compact cold atom gyroscope. Atom interference fringes are observed in the stationary frame and the rotating frame, respectively. The phase shift and contrast of the interference fringe are experimentally investigated. The results show that the contrast of the interference fringe is well held when the platform is rotated, and the phase shift of the interference fringe is linearly proportional to the rotation rate of the platform. The long-term stability, which is evaluated by the overlapped Allan deviation, is 8.5 × 10^-6 rad/s over the integrating time of 1000s.
基金the National Natural Science Foundation of China(Grant Nos.61925301 and 62103026).
文摘A miniaturized atomic spin-exchange relaxation-free(SERF)co-magnetometer measures angular velocity using a balanced polarimetry technique which is easily affected by the laser power.A laser power closed-loop control system is usually used to suppress the fluctuation of the laser power.Although this method can greatly eliminate the fluctuation of the in-loop laser power(the feedback laser),it cannot fully eliminate the fluctuation of the out-of-loop laser power(the signal measurement laser).This leads to SERF gyroscope laser power error,which reduces the inertial measurement accuracy.In this paper,the influence mechanism of the split ratio(the ratio of the in-loop laser power to the out-of-loop laser power)on the out-of-loop laser power control accuracy is analyzed by establishing a laser power transmission model inside and outside the loop.Moreover,a method is developed to improve the out-of-loop laser power stability by optimizing the split ratio.Comparative experiments showed that the relative Allan standard deviation of the out-of-loop laser power decreased from 5.48×10^(-6)to 2.62×10^(-6)at 100 s,and decreased by an order of magnitude from 1.76×10^(-5)to 3.30×10^(-6)at1000 s.Correspondingly,the rate ramp coefficient in the Allan standard deviation curve of the SERF gyroscope test data decreased from 1.312[(°/h)/h]to 0.246[(°/h)/h].And the bias stability increased from 0.032°/h to 0.019°/h.Therefore,the proposed method can improve the long-term stability of the probe laser power and effectively suppress the laser power error of the SERF gyroscope.
基金the National Natural Science Foundation of China(Grant No.11873044).
文摘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,m_(F)=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|m_(F)=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.
基金supported by the State Key Basic Research Program(No.2001CB309307)the National Natural Science Foundation of China(Nos.10974210 and 10474105)
文摘We propose a robust scheme that creates a toroidal magnetic potential on a single-layer atom chip. The wire layout consists of two interleaved Archimedean spirals, which avoids the trapping perturbation caused by the input and output ports. By using a rotation bias field, the minimum of the time-averaged orbiting potential is lifted from zero, and then a relatively smooth and harmonic ring trap is formed. The location of the waveguide is immune to the magnetic variations, as it is only determined by the wire layout. The ring waveguide offers an ideal solution to developing a compact and portable atomic Kyroscope.
基金supported by the National Natural Science Foundation of China (60825305, 61121003)the National Basic Research Program of China (2009CB724002)the Defense Industrial Technology Development Program of China (B2120110002)
文摘Atomic spin gyroscope (ASG) based on comagnetometer is a high sensitive and compact gyroscope for future inertial navigation applications. The start-up time was several hours of the demonstrated ASGs based on 3He-K or21 Ne-Rb-K comagnetometer, and only a few inertial navigation applications allow such a long time for preparation. We report the demonstration of an ASG based on 129Xe-Cs comagnetometer, which decreases the start-up time to 10 minutes and decreases the operation temperature by 40% as well. By operating this ASG in spin exchange relaxation free regime, a sensitivity of 7×10 -5 °/(s Hz1/2) was achieved.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB619304)the National Natural Science Foundation of China(Grant Nos.51072007,91021017,11364030,and 11047018)the Beijing Natural Science Foundation,China(Grant No.1112007)
文摘The electronic structure and magnetic properties of the transition-metal （TM） atoms （Sc-Zn, Pt and Au） doped zigzag GaN single-walled nanotubes （NTs） are investigated using first-principles spin-polarized density functional calculations. Our results show that the bindings of all TM atoms are stable with the binding energy in the range of 6-16 eV. The Sc- and V-doped GaN NTs exhibit a nonmagnetic behavior. The GaN NTs doped with Ti, Mn, Ni, Cu and Pt are antiferromagnetic. On the contrary, the Cr-, Fe-, Co-, Zn- and Au-doped GaN NTs show the ferromagnetic characteristics. The Mn- and Co- doped GaN NTs induce the largest local moment of 4#B among these TM atoms. The local magnetic moment is dominated by the contribution from the substitutional TM atom and the N atoms bonded with it.
