The Effect Of Optical Pumping Rate On Linewidth Narrowing Of Alkali Metal Atomic Magnetic Resonance Spectroscopy

Alkali metal atomic magnetometer has become one of the most sensitive devices for measuring weak magnetic fields.Its signal sensitivity is related to line width and signal-to-noise ratio.The increase of signal will introduce noise and power spreading effects at the same time,which is not conducive to the precise measurement of magnetic fields.In some cases,the line width will decrease as the optical power increases,which is called"ight narrowing".This narrowing effect plays an important role in optimizing the measurement sensitivity of the magnetometer.Based on the phenomenon of "light narrowing",the first theoretical calculation takes the transition system of 87Rb atom D1 line Fg=2?Fe=1 as the research object,It is found that the linewidth of the left and right magnetic resonance peaks measured at different optical pump rates shows a narrowing effect.In order to further analyze,different simplified models are rebuilt and the analytical solutions are obtained.After the analysis of left and right resonance peaks,it is confirmed that the effect of optical pump rate on linewidth narrowing.In the experiment,based on the traditional Mz-type magnetic resonance spectroscopy,the magnetic resonance peaks under different optical powers were measured and successfully observed the phenomenon of line width narrowing,It is found that the linewidth variation of the right resonance peak caused by collision is in good agreement with the theoretical calculation,which further proves the effect of spin exchange collision on linewidth.However,the difference between the left resonance peak and the theoretical calculation is large,which may be due to incomplete consideration,because the resonance linewidth is influenced by many factors,such as gas wall collision,spin exchange relaxation and power broadening effect,Therefore,higher requirements are put forward for optimizing the system model and experimental parameters.