基于相干布居囚禁原理的磁场精密测量研究

发布时间：2019-03-17 10:51

【摘要】：原子磁力仪作为一种量子传感器,由于具有高性能和易于小型化的特点,正逐渐成为磁探系统中的核心传感器。随着磁探系统应用的多元化,磁传感器也向着多个指标的高性能发展。为了满足应用需求,需要对原子磁力仪如何同时保持多个高性能的指标进行研究。本文主要对基于相干布居囚禁原理的磁场测量方案进行了研究,利用双共振原理和线偏振激发的方式,保证了原子磁力仪±0.5nT的绝对精度、20pT/(?)的灵敏度和10Hz的采样率,实现对磁场准确值和变化量的精确测量。双共振原理利用激光光场的调制边带同时激发多个磁子能级,产生相反频移的两个相干布居囚禁信号,从而减小频移机制的影响。线偏振的激发方案消除了因光泵浦作用引起的原子非相干暗态的产生,提高原子利用率和信号信噪比。随后,本文提出了一种基于频移机制的差分方法。这种方法的优点是在保证绝对精度的情况下消除了共模噪声的影响,使磁力仪的灵敏度提高到了 2pT/(?)。接着,本文介绍了基于双共振和线偏振激发原理的相干布居囚禁磁力仪原理样机的相关情况。最后,本文对磁力仪的噪声来源进行了分析,发现噪声主要来源于激光频率抖动引起的频率-幅度噪声,在此基础上提出了一种利用原子气室端面反射方法的饱和吸收光谱锁频技术。该技术具有装置简单、可靠性高和锁频效果好等特点,不仅适合磁力仪的工程化实现,也同样适合其他量子传感器的装置简化,提高在运动平台上的适应性。本文的章节安排:第一章主要介绍了磁场测量的发展与应用需求以及磁传感器的种类、工作原理、优缺点和应用场合;第二章主要介绍了各种原子磁力仪的工作原理、优缺点和国内外发展现状,分析了影响原子磁力仪灵敏度和绝对精度的因素,提出了本课题的研究意义;第三章主要介绍了相干布居囚禁磁力仪原理、双共振原理和线偏振激发原理的实验研究以及利用差分方法实现噪声抑制的方案;第四章主要介绍了相干布居囚禁磁力仪样机的研制情况,包括系统设计和性能测试;第五章主要对磁力仪的噪声进行了分析,并对锁频方法进行了实验研究;第六章主要对本文的内容进行了总结和展望。
[Abstract]:As a kind of quantum sensor, atomic magnetometer is becoming the core sensor in magnetic probe system because of its high performance and easy miniaturization. With the diversification of the application of the magnetic sensor system, the magnetic sensor is developing towards the high performance of many indicators. In order to meet the needs of application, it is necessary to study how to maintain multiple high-performance indicators of atomic magnetometers at the same time. In this paper, the measurement scheme of magnetic field based on coherent population trapping principle is studied. The absolute precision of 卤0.5nT is guaranteed by using the double resonance principle and the mode of linear polarization excitation, and the absolute accuracy of the atomic magnetometer 卤20pT/ (?) The sensitivity of the magnetic field and the sampling rate of 10Hz can be used to measure the accurate value and variation of the magnetic field. The double resonance principle uses the modulated sideband of the laser field to excite multiple magneto-sublevels at the same time to produce two coherent population-trapping signals with opposite frequency shift, thus reducing the influence of the frequency-shift mechanism. The excitation scheme of linear polarization eliminates the generation of non-coherent dark states caused by optical pumping and improves the atomic utilization ratio and signal-to-noise ratio. Then, a difference method based on frequency shift mechanism is proposed in this paper. The advantage of this method is that the influence of common mode noise is eliminated while the absolute precision is guaranteed and the sensitivity of the magnetometer is improved to 2pT/. Then, this paper introduces the prototype of coherent population trapping magnetometer based on double resonance and linear polarization excitation principle. Finally, the noise source of the magnetometer is analyzed. It is found that the noise mainly comes from the frequency-amplitude noise caused by laser frequency jitter. On the basis of this, a frequency-locked technique of saturated absorption spectrum based on the reflection method of atomic gas chamber face is proposed in this paper. The technology has the characteristics of simple device, high reliability and good frequency locking effect. It is not only suitable for the engineering realization of magnetometer, but also suitable for the simplification of other quantum sensors, so as to improve the adaptability on the moving platform. The first chapter mainly introduces the development and application requirements of magnetic field measurement, the types, working principles, advantages and disadvantages of magnetic sensors, and the applications of magnetic sensors. The second chapter mainly introduces the working principle, advantages and disadvantages of various atomic magnetometers and the development situation at home and abroad, analyzes the factors affecting the sensitivity and absolute precision of atomic magnetometers, and puts forward the research significance of this topic. In the third chapter, the principle of coherent population trapping magnetometer, the principle of double resonance and the principle of linear polarization excitation are introduced, and the scheme of noise suppression by using difference method is also introduced. The fourth chapter mainly introduces the development of the prototype of coherent population trapping magnetometer, including system design and performance testing, chapter 5 mainly analyzes the noise of the magnetometer, and carries on the experimental research on the frequency locking method. The sixth chapter summarizes and looks forward to the content of this paper.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TP212

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