In-situ measurement and close-loop control of atomic number density in an optically pumped magnetometer based on light absorption

Abstract

For optically pumped atomic magnetometers, the attenuation of the pumping light through the alkali-metal vapor due to light absorption is related to the number density of alkali-metal atoms. In this study, we propose an in-situ measurement and control method of atomic number density based on light absorption in the temperature range of 60 °C–160 °C, which is a much wider temperature range than considered in previous reports. A light absorption-density model is proposed to accurately describe the relationship between the light transmittance and the atomic number density. The influence of static and oscillating magnetic fields on the atomic number density measurement is also analyzed. Based on this model, a close-loop system is constructed to control the atomic number density using an electric heater. The experimental results exhibit that the proposed method can limit the fluctuation of the atomic number density in the range of 1.4%.

High-precision alkali-atom density measurement and control methods using light absorption for dual-beam SERF magnetometers

“…Yin et al analyzed the influence of modulated magnetic fields on the transmitted intensity and achieved temperature control in SERF magnetometers by detecting the transmitted pump light intensity [14] . Liu et al measured and controlled atomic number density over a wide temperature range based on light absorption [15] . The influence of static and oscillating magnetic fields on atomic number density measurements was also analyzed.…”