Faraday detection method for removing modulation amplitude and light-intensity variation influences

Abstract

A Faraday detection method for removing modulation amplitude and light-intensity variation influences relates to a method for accurately removing measurement errors caused by modulation amplitude and light-intensity variation in the process of measuring light polarization tiny rotating angles by using a Faraday modulator. According to the method, a digital phase-locked amplifier module is adopted to measure primary harmonic signals and secondary harmonic signals in signals to be demodulated, combining light-intensity signals of Faraday modulator incident light, parameters in the primary harmonic signals and related to the modulation amplitude and the incident light light-intensity are removed through resolving, and finally light polarization tiny rotating angles not influenced by modulation amplitude and light-intensity variation are obtained. The Faraday detection method can remove measurement errors caused by modulation amplitude and unstable incident light light-intensity when the Faraday modulator is used for measuring the light polarization tiny rotating angles, remarkably improves long-time measurement accuracy, and can be used in the process of using atomic spin magnetometers, atomic spin gyros and other instruments to accurately measure light polarization tiny rotating angles.

Description

technical field [0001] The invention relates to a Faraday detection method for eliminating the influence of modulation amplitude and light intensity fluctuations, which can be used as a precise measurement method for the tiny rotation angle of light polarization in instruments and equipment such as atomic magnetometers and atomic spin gyroscopes, and can also be used as a method for detecting Faraday A method for real-time monitoring of modulator modulation amplitude and incident light intensity. Background technique [0002] The Faraday modulator detection method is a high-precision light polarization micro-rotation angle measurement method. Compared with the photoelastic modulation detection method and the polarization beam splitter prism differential detection method, it has higher detection sensitivity. Therefore, the atomic magnetometer and Atomic spin gyroscopes and other precision measuring instruments have extremely important and broad application prospects, and thei...

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Problems solved by technology

However, this also leads to the fact that the modulation amplitude of paramagnetic magneto-optic crystals is more susceptible to fluctuations in the modulating magnetic field

At the same time, the Verdet constant of the paramagnetic magneto-optic crystal has a strong dependence on the temperature and the wavelength of the incident light. The change of the temperature of the magneto-optic crystal and the wavelength of the incident light will cause the fluctuation of the Verdet constant of the magneto-optic crystal, and then affect the Stabilization of Modulation Amplitude of Faraday Modulator

The traditional Faraday detection method mainly uses the first harmonic signal to measure the small rotation angle of linear polarization, and regards the modulation amplitude of the Faraday modulator and the light intensity of the incident light as fixed values ​​to solve the small rotation angle. Therefore, the actual In this case, the modulation amplitude of the Faraday modulator and the fluctuation of the incident light intensity will bring errors to the detection results, which affects the measurement accuracy of the Faraday modulator for small rotation angles, which greatly limits its application in atomic magnetometers and atomic spin gyroscopes. applications in precision measurement

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