We demonstrated a new method of atom detection by means of the magnetic optical effect. The number density of the atom cloud was measured by detecting the rotation angle of the polarization plane of linearly polarized...We demonstrated a new method of atom detection by means of the magnetic optical effect. The number density of the atom cloud was measured by detecting the rotation angle of the polarization plane of linearly polarized probe light when propagating inside the atomic cloud. Detuning, the magnetic field and light intensity dependencies of the rotation angle were studied theoretically and experimentally to find the best parameter for atom detection. In this way, we managed to achieve a rotation angle of 0.22 rad with a signal to noise ratio （SNR） of 75 and a contrast of 87.5%.展开更多
We theoretically investigate an open four-level atomic system interacting with control,probe and microwave fields.When there is no repumping light and a microwave field is applied,the probe light can be absorbed or am...We theoretically investigate an open four-level atomic system interacting with control,probe and microwave fields.When there is no repumping light and a microwave field is applied,the probe light can be absorbed or amplified,which has different features than those of a system whose populations are pumped into only one ground state.In this system the microwave field and the population distributions of the ground states can be used as switches to control the propagation of the probe light.展开更多
We report the recent progress of our pulsed optically pumped（POP） vapor cell rubidium clock with dispersive detection.A new compact physics package is made.A rubidium cell with a high precision buffer gases mixing r...We report the recent progress of our pulsed optically pumped（POP） vapor cell rubidium clock with dispersive detection.A new compact physics package is made.A rubidium cell with a high precision buffer gases mixing ratio is obtained,and the temperature controlling system is renovated to reduce fractional frequency sensitivity to temperature variation.The resolution of the servo control voltage is also optimized.With these improvements,a clock frequency stability of 3.53×10-13 at 1s is obtained,and a fractional frequency stability of 4.91×10-15 is achieved at an average time of τ=2000 s.展开更多
We report a locking mode in which the local oscillator （LO） is locked to an atomic fountain and calibration of the residual frequency drift （RFD）. In this running mode, the locked LO outputs a standard frequency s...We report a locking mode in which the local oscillator （LO） is locked to an atomic fountain and calibration of the residual frequency drift （RFD）. In this running mode, the locked LO outputs a standard frequency signal, and a short-term fractional frequency stability of 2.7 × 10-13-1/2 is achieved. Due to the frequency drift of the LO in free running mode, a systematic frequency bias, or RFD, exists after being locked by the atomic fountain. We analyze and measure the RFD with a value of -3（2） × 10-16. A sectionalized post-process method is adopted to calibrate the RFD.展开更多
The environmental perturbation on atoms is a key factor restricting the performance of atomic frequency standards, especially in the long-term scale. In this Letter, we perform a real-time noise distinguish（RTND） to...The environmental perturbation on atoms is a key factor restricting the performance of atomic frequency standards, especially in the long-term scale. In this Letter, we perform a real-time noise distinguish（RTND） to an atomic clock to decrease the uncertainty of the atomic clock beyond the level that is attained by the current controlling method. In RTND, the related parameters of the clock are monitored in real time by using the calibrated sensors, and their effects on the clock frequency are calculated. By subtracting the effects from the error signal, the local oscillator is treated as equivalently locked to the unperturbed atomic levels. In order to perform quantitative tests, we engineer time-varying noise much larger than the intrinsic noise in our fountain atomic clock. By using RTND, the influences of the added noises are detected and subtracted precisely from the error signals before feeding back to the reference oscillator. The result shows that the statistical uncertainty of our fountain clock is improved by an order of magnitude to 2 × 10^（-15）. Besides, the frequency offset introduced by the noise is also corrected, while the systematic uncertainty is unaffected.展开更多
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB921504)the National Natural Science Foundation of China (Grant No. 10974210)
文摘We demonstrated a new method of atom detection by means of the magnetic optical effect. The number density of the atom cloud was measured by detecting the rotation angle of the polarization plane of linearly polarized probe light when propagating inside the atomic cloud. Detuning, the magnetic field and light intensity dependencies of the rotation angle were studied theoretically and experimentally to find the best parameter for atom detection. In this way, we managed to achieve a rotation angle of 0.22 rad with a signal to noise ratio （SNR） of 75 and a contrast of 87.5%.
基金Supported by the Knowledge Innovation Program of Chinese Academy of Sciences under Grant No KGCX3-SYW-405the State Key Development Program for Basic Research(KGCX3-SYW-405)+1 种基金the National Basic Research Program of China under Grant Nos 2005CB724507 and 2006CB921202National Natural Science Foundation of China(10974210).
文摘We theoretically investigate an open four-level atomic system interacting with control,probe and microwave fields.When there is no repumping light and a microwave field is applied,the probe light can be absorbed or amplified,which has different features than those of a system whose populations are pumped into only one ground state.In this system the microwave field and the population distributions of the ground states can be used as switches to control the propagation of the probe light.
基金supported by the National Natural Science Foundation of China under Grant Nos.91536220 and 11504393
文摘We report the recent progress of our pulsed optically pumped（POP） vapor cell rubidium clock with dispersive detection.A new compact physics package is made.A rubidium cell with a high precision buffer gases mixing ratio is obtained,and the temperature controlling system is renovated to reduce fractional frequency sensitivity to temperature variation.The resolution of the servo control voltage is also optimized.With these improvements,a clock frequency stability of 3.53×10-13 at 1s is obtained,and a fractional frequency stability of 4.91×10-15 is achieved at an average time of τ=2000 s.
基金supported by the National Natural Science Foundation of China under Grant Nos.61275204,91336105,and 11404353
文摘We report a locking mode in which the local oscillator （LO） is locked to an atomic fountain and calibration of the residual frequency drift （RFD）. In this running mode, the locked LO outputs a standard frequency signal, and a short-term fractional frequency stability of 2.7 × 10-13-1/2 is achieved. Due to the frequency drift of the LO in free running mode, a systematic frequency bias, or RFD, exists after being locked by the atomic fountain. We analyze and measure the RFD with a value of -3（2） × 10-16. A sectionalized post-process method is adopted to calibrate the RFD.
基金supported by the National Natural Science Foundation of China under Grant Nos.61275204 and 91336105
文摘The environmental perturbation on atoms is a key factor restricting the performance of atomic frequency standards, especially in the long-term scale. In this Letter, we perform a real-time noise distinguish（RTND） to an atomic clock to decrease the uncertainty of the atomic clock beyond the level that is attained by the current controlling method. In RTND, the related parameters of the clock are monitored in real time by using the calibrated sensors, and their effects on the clock frequency are calculated. By subtracting the effects from the error signal, the local oscillator is treated as equivalently locked to the unperturbed atomic levels. In order to perform quantitative tests, we engineer time-varying noise much larger than the intrinsic noise in our fountain atomic clock. By using RTND, the influences of the added noises are detected and subtracted precisely from the error signals before feeding back to the reference oscillator. The result shows that the statistical uncertainty of our fountain clock is improved by an order of magnitude to 2 × 10^（-15）. Besides, the frequency offset introduced by the noise is also corrected, while the systematic uncertainty is unaffected.
