When the ground state hyperfine splitting of alkali metal vapor atoms is well optically resolved, the spin coherence on one hyperfine sublevel can be generated directly or indirectly by pumping the same or the other s...When the ground state hyperfine splitting of alkali metal vapor atoms is well optically resolved, the spin coherence on one hyperfine sublevel can be generated directly or indirectly by pumping the same or the other sublevel respectively. We experimentally studied the pump power dependence of the field response of a Bell-Bloom magnetometer for the two pumping schemes in a paraffin coated ^87Rb vapor cell. We find that although the maximum field response is achieved by combining the two pumping schemes, indirect pumping alone can do nearly as good while being much simpler to operate. We have achieved a sensitivity of 100 fT/Hz^1/2 with a single indirect pump at room temperature.展开更多
We theoretically and experimentally study the optimal duty cycle and pumping rate for square-wave amplitudemodulated Bell–Bloom magnetometers.The theoretical and the experimental results are in good agreement for dut...We theoretically and experimentally study the optimal duty cycle and pumping rate for square-wave amplitudemodulated Bell–Bloom magnetometers.The theoretical and the experimental results are in good agreement for duty cycles and corresponding pumping rates ranging over 2 orders of magnitude.Our study gives the maximum field response as a function of duty cycle and pumping rate.Especially,for a fixed duty cycle,the maximum field response is obtained when the time averaged pumping rate,which is the product of pumping rate and duty cycle,is equal to the transverse relaxation rate in the dark.By using a combination of small duty cycle and large pumping rate,one can increase the maximum field response by up to a factor of 2 or π /2,relative to that of the sinusoidal modulation or the 50% duty cycle square-wave modulation respectively.We further show that the same pumping condition is also practically optimal for the sensitivity due to the fact that the signal at resonance is insensitive to the fluctuations of pumping rate and duty cycle.展开更多
基金supported by the Natural Science Foundation of Shanghai(Grant No.16ZR1402700)the National Natural Science Foundation of China(Grant No.91636102)the National Key Research and Development Program of China(Grant No.2016YFA0302000)
文摘When the ground state hyperfine splitting of alkali metal vapor atoms is well optically resolved, the spin coherence on one hyperfine sublevel can be generated directly or indirectly by pumping the same or the other sublevel respectively. We experimentally studied the pump power dependence of the field response of a Bell-Bloom magnetometer for the two pumping schemes in a paraffin coated ^87Rb vapor cell. We find that although the maximum field response is achieved by combining the two pumping schemes, indirect pumping alone can do nearly as good while being much simpler to operate. We have achieved a sensitivity of 100 fT/Hz^1/2 with a single indirect pump at room temperature.
基金Project supported by the National Natural Science Foundation of China(Grant No.11074050)
文摘We theoretically and experimentally study the optimal duty cycle and pumping rate for square-wave amplitudemodulated Bell–Bloom magnetometers.The theoretical and the experimental results are in good agreement for duty cycles and corresponding pumping rates ranging over 2 orders of magnitude.Our study gives the maximum field response as a function of duty cycle and pumping rate.Especially,for a fixed duty cycle,the maximum field response is obtained when the time averaged pumping rate,which is the product of pumping rate and duty cycle,is equal to the transverse relaxation rate in the dark.By using a combination of small duty cycle and large pumping rate,one can increase the maximum field response by up to a factor of 2 or π /2,relative to that of the sinusoidal modulation or the 50% duty cycle square-wave modulation respectively.We further show that the same pumping condition is also practically optimal for the sensitivity due to the fact that the signal at resonance is insensitive to the fluctuations of pumping rate and duty cycle.
