Random noise taming under phase control: spectral manipulation of an optically pumped atomic magnetometer by random...

Optically pumped atomic magnetometer (OPAM), as a highly sensitive quantum sensor, is often significantly disturbed by low-frequency random noise, which seriously limits its measurement robustness. Motivated by this problem, we systematically studied the influence of various parameters of the statistical field related to random telegraph noise (RTN) on the dynamics and spectral characteristics of the OPAM, both theoretically and experimentally. The investigation revealed that the OPAM output spectrum shows a phase sensitivity similar to that induced by the squeezed vacuum field to the relative phase ϕ between the statistical field and the coherent driving field, and its physical essence originates from the phase-dependent reservoir formed by the statistical field. Specifically, the system spectrum is periodically modulated to ϕ, showing complementary regulation behavior of spectral peak and linewidth: when ϕ=90^∘, the system is almost insensitive to the RTN noise parameters, showing good robustness; however, when ϕ=0^∘, the system is highly responsive to the RTN parameters, showing obvious spectral broadening effect. Our results not only provide what we believe to be a new phase control strategy for the optimization of the OPAM under the background of low-frequency noise, but also provide theoretical and experimental path for the development of noise spectrum precision measurement and dynamical decoupling technology based on OPAM.