Magnetic Field Detection Technology Research Based On Cavity Optomechanical Structure

The development of navigation systems and the popularization of mobile terminals have placed higher demands on the accuracy of navigation equipment.In extreme cases where the GPS is paralyzed,assisted navigation technology will play a vital role.As a part of the auxiliary navigation system,the development of the magnetometer will promote the rapid development of navigation technology.In addition,the high-precision magnetometer has a wide range of applications in military,medical,and industrial fields.Therefore,researching high-precision magnetometer has far-reaching scientific significance and important application value.As the traditional magnetometer has the problems of complicated processing technology,high manufacturing cost,low yield,poor reliability,and difficult to integrate with the current CMOS circuit,it is necessary to designed a new magnetometer.In this thesis,a Lorentz force cavity optomechanical magnetometer is proposed.The main work and contributions of this thesis are as follows:1.A Lorentz force cavity optomechanical magnetometer is proposed based on the high-efficiency optical-mechanical energy coupling characteristics of the cavity optomechanical structure.The parameters of the differential/non-differential structure are optimized by COMSOL and the corresponding signal conditioning circuit are designed.The performances of the structure,such as stability,resonance characteristics,sensitivity and power consumption are also simulated and analyzed by COMSOL,and the resolution and noise characteristics are theoretically analyzed in this thesis.The simulation results show that when the input laser intensity is 200 ?W and the current intensity in the Lorentz coil is 1 mA,the sensitivity of the non-differential structure is 1?T/Hz,and the sensitivity of differential structure reaches 0.5 ?T/Hz.2.On the basis of simulation result,the Lorentz force cavity optomechanical magnetometer is processed.Further more,a test platform is built to test and analyze the performances of the magnetometer,which includes stability,resonance characteristics,coupling efficiency,sensitivity,resolution,noise characteristics and power consumption.Test results show that when the input laser intensity is 200 ?W and the current intensity in the Lorentz coil is 1 mA,the sensitivity of the non-differential structure is 1.91 ?T/Hz,and the detection resolution is 1.88 ?T/Hz1/2.3.By analyzing the theoretical formulas of the sensitivity and resolution of the magnetometer,an improved Lorentz force cavity optomechanical magnetometer is proposed.Under the same input laser intensity and input current magnitude,the sensitivity of the non-differential structure is up to 10 nT/Hz.Compared with the structure before improvement,the detection sensitivity is increased by 100 times.The magnetometer researched and designed in this thesis can promote the further extensive application of the cavity optomechanical structure in the technical field of high-precision detection,navigation,and positioning.