Precise measurement of a weak radio frequency electric field using a resonant atomic probe<xref rid="cpb_29_3_033201fn1" ref-type="fn">*</xref><fn id="cpb_29_3_033201fn1"><label>*</label><p>Project supported by the National Key R&D Program of China (Grant No. 2017YFA0304203), the National Natural Science Foundation of China (Grant Nos. 61475090, 61675123, 61775124, and 11804202), the State Key Program of National Natural Science of China (Grant Nos. 11434007 and 61835007), and Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China (Grant No. IRT 17R70).</p></fn>

Precise measurement of a weak radio frequency electric field using a resonant atomic probe**

Project supported by the National Key R&D Program of China (Grant No. 2017YFA0304203), the National Natural Science Foundation of China (Grant Nos. 61475090, 61675123, 61775124, and 11804202), the State Key Program of National Natural Science of China (Grant Nos. 11434007 and 61835007), and Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China (Grant No. IRT 17R70).

Hao Liping¹, Xue Yongmei¹, Fan Jiabei¹, Bai Jingxu¹, Jiao Yuechun^{1, 2}, Zhao Jianming^{1, 2, †}

Measurements of the lock-in output of the probe transmission (red squares) and signal fields E_S (blue circles) by EIT-AT spectra versus the square root of the output power, PRF , of the function generator for (a) signal field frequency ω_S ∼ 2π × 2.18 GHz and (b) ω_S ∼ 2π × 1.32 GHz. The black line is the calculation of equation ERF=30PRFg/d . The detectable minimum of signal field E_{S_min} = 1.36 ± 0.04 mV/m in (a) and 1.33 ± 0.02 mV/m in (b). The error bars display the standard error of two independent measurements. The inset demonstrates the lock-in output of the probe transmission.