High-Precision Measurement Method for Unshielded Low-Frequency and DC Electric Fields Based on Dipole Gas Stark Effect

Accurate measurement of low-frequency and DC electric fields holds significant importance in industrial inspection, environmental monitoring, and fundamental scientific research. However, traditional measurement methods face severe challenges in the low-frequency regime. Although quantum sensors based on Rydberg atoms exhibit high sensitivity, they fail under low-frequency and DC electric fields due to shielding effects caused by free electrons on the gas cell surface. This paper proposes a novel electric field measurement device based on the Stark effect of dipolar gas molecules, utilizing HCl as the sensing medium. By combining infrared excitation via a quantum cascade laser (QCL) and dual-modulation demodulation technology, unshielded and high-precision electric field detection is achieved. Experimental results demonstrate a sensitivity of 0.1 V/m within the 0.1 Hz to 1 kHz frequency range and a DC field measurement error below ± 0.5 V/m. Compared to traditional Rydberg sensors, the signal attenuation rate at 50 Hz power-frequency electric fields decreases from 80% to 5%, significantly enhancing anti-shielding performance. Through optimized anti-adsorption gas cell design and dynamic polarization calibration, system stability in complex environments is effectively ensured. This research provides an innovative solution for low-frequency electric field measurement, with critical applications in power system monitoring and bioelectromagnetic research, while offering theoretical and practical insights for the engineering implementation of quantum sensing technologies.