PRECISE MAGNETIC FIELD DETECTION METHOD AND SYSTEM BASED ON OPTICAL CAVITY OF MAGNETOSTRICTIVE MATERIAL

摘要

Disclosed are a precise magnetic field detection method and system based on an optical cavity of a magnetostrictive material. The method comprises the following steps: combining a magnetostrictive material with a high reflectivity cavity mirror to form an optical cavity, the cavity length of the optical cavity changing with a magnetic field to be measured; locking laser at the resonance frequency of the optical cavity, so that the laser frequency completely follows the cavity length of the optical cavity; converting a direct-current magnetic field signal to be measured into an alternating-current signal for measurement by loading a modulated magnetic field according to the nonlinear characteristic of the magnetostrictive effect, to avoid low-frequency noise; and realizing low-noise detection of laser frequency change to obtain a magnetic field signal to be measured. According to the method, the magnetostrictive material forms the optical cavity, and the laser frequency is further locked in the optical cavity, so that weak magnetic field change is converted into laser frequency change, and high-sensitivity magnetic field detection under normal temperature condition is realized.