Design of Transparent Nonmagnetic Electric Heating Film Based on MEMS Technology for Microalkali Metal Vapor Cell

Aiming to address the limitations of traditional heating films in balancing the magnetic field suppression and uniform heating in spin-exchange relaxation-free (SERF) atomic magnetometer applications, this article designs a transparent, nonmagnetic electric heating film based on the MEMS technology, in which indium tin oxide (ITO) is used as the core heating material. First, a model is developed to analyze the spatial magnetic field strength induced by current flowing in different directions through the wiring. The layout design of the heating film is then optimized through the quantitative analysis and simulation. Next, ITO, a transparent material, is selected and processed using the MEMS technology. This successfully addresses the condensation issue at the optical apertures of traditional flexible printed circuit (FPC) heating films, which is caused by uneven heating, thereby improving the heating uniformity. The final experiment validated the feasibility and effectiveness of the design. The experimental results show that the magnetic flux density of the designed heating film under dc conditions is 0.8154 nT/mA. Under the same heating conditions, the temperature variance in the vapor cell area decreased from 0.0125 °C2 for traditional heating films to 0.0103 °C2, with a particularly significant temperature increase observed in the optical aperture region. Experimental data confirm that the MEMS-based transparent heating film developed in this study demonstrates significant advantages in both magnetic field suppression and heating uniformity.