Toward Absolute Measurements of Far-Field Microwave Magnetic Field by Atomic Sensor Based on Double Radiooptical Resonance

By using Cs atomic sensor, the differences between the measurement results of double radiooptical resonance (DROR) and the ratio of Doppler amplitude to DROR signal (Doppler/DROR) for the far-field microwave magnetic field were illustrated experimentally. The effects of laser power and atomic sensor temperature to the DROR and Doppler/DROR ratio were investigated. At constant laser power, Cs atomic cell temperature and microwave magnetic field strength, the maximum deviations for DROR and Doppler/DROR ratio were calculated over time. The fluctuation of the Doppler/DROR ratio measurement results was calculated approximately as 0.5 dB in 24-h measurement time interval. On the other hand, the fluctuation of the measured DROR values was calculated as 0.9 dB in the same time interval. As a consequence, Doppler/DROR ratio measurements yield better and repeatable results by comparison with DROR measurements.