1School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100083 2Graduate School of China Academy of Engineering Physics, Beijing 100193 3Department of Aerospace Science and Technology, Space Engineering University, Beijing 101416
Abstract：There is a common sense view for atomic magnetometers that their spin-projection-noises (SPNs) are inversely proportional to $\sqrt{{T_2}}$, where $T_2$ is the transverse relaxation time. We analyze the current atomic magnetometer types and give a counter-example of this common sense, which is the all-optical spin precession modulated three-axis atomic magnetometer proposed by our group in 2015. Unlike the other atomic magnetometers, the SPN of this kind of atomic magnetometers is proportional to $\sqrt{{T_2}}$ due to the fact that the scale factor between $P_x$ and $B$ can be unrelated to the transverse relaxation time $T_2$. We demonstrate this irrelevance experimentally and analyze the SPN theoretically. Using short-pulse ultra-high power laser to fully polarize the atoms, the phenomenon that SPN decreases with $T_2$ may also be demonstrated experimentally and a new tool for researching SPN in atomic magnetometers may be realized.
2019, Vol. 36 
