基于里德堡原子的工频电场测量

Power Frequency Electric Field Measurement Based on Rydberg Atoms

里德堡原子是主量子数n很大的高激发态原子。里德堡原子由于具有大极化率特性,其对外部电场十分敏感,原子能级偏移与电场直接关联,可以用来实现对电场强度和频率的精确测量。该文通过双光子激发的方式实现室温中铯原子20S_(1/2)里德堡态的制备,并基于里德堡原子的电磁诱导透明(electromagnetically induced transparency,EIT)光谱实现了工频电场的测量。实验中研究了工频电场的幅值和频率与EIT的频移关系,实现对工频电场强度和频率的测量。实验中EIT光谱频移是测量电场特性的关键,利用电光调制器对探测光相位进行调制,在EIT光谱两侧产生的边带峰与主峰频率间隔则严格等于电光调制器射频源频率,以此频率作为校准基准实现EIT光谱频移的准确测量。设计了一种微型光纤结构的传感器,可以实现电场的远距离测量。该研究方案对室外高压工频电场的可溯源精确测量及工程应用具有重要参考价值,适用于新型电力系统建设的测量要求。

Rydberg atoms are highly excited atoms with a large principal quantum number n. Rydberg atoms are very sensitive to external electric fields due to their large polarizability. As the atomic energy level shift is directly related to the electric field, Rydberg atoms can be used to accurately measure the strength and frequency of external electric field. In this paper, the preparation of 20S_(1/2) Rydberg state of cesium atoms at room temperature is realized by two-photon excitation, and the measurement of electric field at industrial frequency is realized based on electromagnetically induced transparency(EIT) spectroscopy of Rydberg atoms. In the experiment, the relationship between the amplitude and frequency of the power frequency electric field and the frequency shift of the EIT is studied, and the measurements of the strength and frequency of the power frequency electric field are realized. Meanwhile, the frequency shift of the EIT spectrum is the key to measuring the characteristics of the electric field. We adopt the electro-optic modulator to modulate the phase of the probe light. The frequency interval between the side band peak generated on both sides of the EIT spectrum and the main peak is strictly equal to the frequency of the radio frequency source of the electro-optic modulator. This frequency acts as a calibration criteria to enable accurate measurement of the EIT spectral frequency shift. We design a micro all-fiber structure sensor, which can realize the remote measurement of electric field. The research scheme in this paper has important reference value for the traceable and accurate measurement and engineering application of outdoor high-voltage power frequency electric field, and it is suitable for the measurement requirements of new power system construction.