Method for measuring microwave electric field by utilizing double-dark state system

Abstract

The invention discloses a method for measuring a microwave electric field by utilizing a double-dark state system. The method is characterized in that laser provided by an external cavity semiconductor laser is split by a dichroscope into probe laser and coupling laser, and the probe laser and the coupling laser enter a rubidium atom vapor chamber in the same direction through half-wave plates and a polarization beam splitter; the two half-wave plates adjust incident light intensity of a probe laser field and a coupling laser field respectively to enable the control field >> the probe field; the probe laser is locked in a rubidium Rydberg atom 5S1 / 2 (F = 1)-5P3 / 2 transition line, and the control laser is locked in a rubidium Rydberg state atom 5S1 / 2 (F = 2)-5P3 / 2 transition line; a frequency doubling laser provides coupling laser, and adjusts the coupling laser to couple in energy level 5P3 / 2-53D5 / 2 resonance frequency; a microwave analog signal generator provides a power-adjustable microwave signal to couple transition between Rydberg atom state vectors 53D5 / 2-54P3 / 2, and thus transmission peak of EIT of Rydberg atoms splits; and a photoelectric detector detects absorption characteristics of the probe laser, and transmission peak line wide space represents electric field intensity of the microwave signal. The method can greatly narrow transmission peak line width and improve detection precision and sensitivity.

Description

Technical field [0001] The invention relates to a microwave electric field measurement method. Background technique [0002] In recent years, electric field measurement based on Rydberg atoms has been a hot research topic in the field of microwave electric field precision measurement. Due to its large polarizability, low ionization threshold and large electric dipole moment, it is very sensitive to external electromagnetic fields and can be used to measure electric field strength, especially microwave electric field strength. In 2012, Sedlacek et al. used the atomic resonance method to measure the electric field in the rubidium bubble. Theoretically, this method can measure the microwave electric field less than 100nm / cm, and the minimum electric field intensity measured in the experiment is 8μV / cm. In 2016, Simons et al. used the frequency detuning method in the Rydberg atom to improve the sensitivity of detecting electric fields. The sensitivity of the frequency detuning meth...

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Problems solved by technology

The principle of this patent application is to use the difference between the interference fringe displacement caused by the microwave field and the fringe displacement without the microwave field to characterize the microwave electric intensity. The energy level structure is a single electromagnetically induced transparency (EIT) system, which uses the coherence time of the cold atom Rydberg state Long improves the detection accuracy, but requires a complex cooling device structure, and the measurement accuracy is limited

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