Method and device for improving microwave electric field intensity measurement signal-to-noise ratio through Zeeman frequency modulation

Abstract

The invention provides a method and device for improving the microwave electric field intensity measurement signal-to-noise ratio through Zeeman frequency modulation. The method comprises the following steps: the frequency of coupling light is locked on the resonance transition of the intermediate state and the Rydberg state 1; the microwave frequency is locked on the resonance transition of the Rydberg state 1 and the Rydberg state 2, the frequency of the detection light is scanned near the resonance transition frequency of the ground state and the intermediate state, and the spectrum of thedetection light after penetrating through an atom pool is measured so as to obtain the spectrum of the AT split signal of the Rydberg electromagnetic induction transparency EIT; the position of the atomic energy level of the sample is modulated by using an alternating-current magnetic field, and frequency modulation is performed on the spectrum; and the spectrum of the AT split signal of the Rydberg electromagnetic induction transparent EIT is demodulated to obtain a dispersive frequency discrimination signal of the EIT-AT split spectrum. According to the method and device, the atomic energy level is modulated through the alternating magnetic field, frequency modulation is equivalent to spectrum frequency modulation, the problem of residual amplitude does not exist naturally, and meanwhilean experiment system is simpler and more convenient.

Description

technical field [0001] The invention belongs to the technical field of weak signal detection, and in particular relates to a method and a device for improving the signal-to-noise ratio of microwave electric field strength measurement through Zeeman frequency modulation. Background technique [0002] Due to its large electric dipole moment, Rydberg atoms are very sensitive to external fields, and the transition frequency of adjacent Rydberg energy levels is in the microwave band, so they have great application prospects in the measurement of microwave electric field strength and microwave communication. . The Electromagnetic Induced Transparency (EIT) effect is the quantum coherence effect produced by the interaction between atoms and electromagnetic waves, which reduces the absorption of weak probe light at the atomic resonance and even becomes completely transparent. The EIT effect can be used to slow down the speed of light, measure the magnetic field, and store light. A...

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Problems solved by technology

However, when the electro-optic modulator (EOM) is used for frequency modulation, it often brings residual laser amplitude modulation, which is not desirable, although [Optics Express 25, 8628 (2017)] of the literature system uses feedback to reduce the EOM frequency modulation. Residual laser amplitude modulation, but additional system complexity

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