In Situ Suppression of Thermal–Magnetic Coupling Noise in Atomic Sensors

Spin-based sensors, such as magnetometers and comagnetometers, require precise control of thermal conditions and magnetic fields to achieve optimal performance. Thermal–magnetic coupling noise, induced by heating systems, is one of the limiting factors for sensitivity improvement. In this article, the in situ suppression method is proposed to eliminate thermal–magnetic coupling noise by employing the double-layer heater with dynamically adjustable current ratios. The in situ method is verified across two distinct systems, including a commercial magnetometer and the self-developed comagnetometer. For the magnetometer system, the heating-induced magnetic interferences of the double-layer heater along three directions have been decreased by over two orders compared to a conventional heater. Similarly, the total magnetic flux density has been suppressed by more than 78%. Furthermore, the thermal–magnetic coupling noise in the K–Rb–²¹Ne comagnetometer equipped with the double-layer heater is in situ suppressed to 6.54\times 10^{-9\circ } /s/Hz {}^{\mathrm {12}} (0.01 fT/Hz {}^{\mathrm {12}}) at 1 Hz, achieving a noise reduction of 22 dB compared to the ex situ method and 24-dB suppression relative to a conventional heater. Besides, the double-layer heater ensures a uniform and stable thermal field across the vapor cell, with a temperature variance of less than 0.65~^{\circ } C and a temperature fluctuation 65% lower than that of a conventional heater. This work advances ultrasensitive quantum sensors by providing an effective method to in situ suppress thermal–magnetic coupling noise.