基于激光自混合效应的多物理参数同步测量方法研究

发布时间：2018-06-26 00:55

本文选题：激光自混合效应 + 激光调制　；参考：《中国科学技术大学》2016年博士论文

【摘要】：激光自混合干涉技术具有结构简单、造价低廉及非接触测量等显著优点。随着激光自混合效应研究的深入和先进制造技术的提升,多物理参数的同步高分辨率测量,已经成为激光自混合技术和先进光学检测领域发展的重要需求之一。本文在研究多重光反馈、三角波激光调制的基础上,搭建了基于激光自混合效应的高精度光纤式的振动和角度同步测量系统、速度和位移的同步测量系统以及运动速度的二维信息同步获取系统,并进行了相关实验,主要研究工作如下1.基于激光自混合效应的三镜腔理论模型,系统地分析了弱反馈条件下,激光器参数对激光自混合信号的影响,结果表明,在激光器谐振腔1-20mm长度和1.526-1.933折射率范围内,减小谐振腔的长度和有效折射率,有助于增强激光自混合效应。2.提出了一种基于激光自混合效应的颗粒物粒径反演的理论方法,结合随机信号理论和计算机仿真,模拟了颗粒物后向散射光引起的激光自混合信号变化特征,系统地分析了颗粒物粒径对激光自混合信号的影响,对仿真信号的功率谱密度进行洛伦兹拟合,得到粒径在0.5-3μmm范围内气溶胶粒子的反演粒径,误差小于11%。3.阐述了激光自混合效应中的双重光反馈效应,通过模拟仿真和实验验证分析了双重光反馈效应的来源以及影响因素。理论和实验结果表明,激光自混合技术中的双重光反馈效应是由激光器的出射激光在外腔中两次反射引起的,两次反射光的有效强度比值和有效相位差值是双重光反馈效应程度的重要影响因素。4.搭建了基于激光自混合效应的角度和振幅同步测量的单通道光纤系统,在0.990°-1.029°的角度范围和0-3000mVpp的振动范围,角度和振动测量误差分别优于12.1%和1%,测量精度可达387.5nm。5.采用三角波调制方案,搭建了基于激光自混合效应的速度和位移同步测量的单通道光纤系统,分析了三角波的幅度、频率和不对称度对实验信号的影响,选择合适的调制信号。在0.016-0.47m/s的速度范围和1-23mmm的位移范围,速度和位移误差分别优于5.3和9.8%。6.搭建了基于激光自混合技术的双通道光纤测速系统,实现了两个通道速度的同步测量,入射角为45°时,两个通道的测速误差分别是7.3%和8.6%。通过入射光对称和垂直的测速方法,能够将测量误差分别减小为5.2%和6.8%。
[Abstract]:Laser self-mixing interferometry has the advantages of simple structure, low cost and non-contact measurement. With the development of laser self-mixing effect and advanced manufacturing technology, synchronous high-resolution measurement of multi-physical parameters has become one of the important requirements in the field of laser self-mixing technology and advanced optical detection. Based on the study of multiplex optical feedback and triangle-wave laser modulation, a high-precision optical fiber vibration and angle synchronous measurement system based on laser self-mixing effect is built in this paper. The synchronous measurement system of velocity and displacement and the two dimensional information acquisition system of motion velocity are used in this paper. The relevant experiments are carried out. The main research work is as follows: 1. Based on the three-mirror cavity theory model of laser self-mixing effect, the influence of laser parameters on laser self-mixing signal under weak feedback condition is systematically analyzed. The results show that in the range of 1-20mm length and 1.526-1.933 refraction index of laser resonator, Reducing the length and effective refractive index of the resonator is helpful to enhance the laser self-mixing effect. A theoretical method of particle size inversion based on laser self-mixing effect is proposed. Combining with random signal theory and computer simulation, the variation characteristics of laser self-mixing signal caused by backscattering light of particles are simulated. The influence of particle size on laser self-mixing signal is analyzed systematically. The power spectral density of simulated signal is fitted by Lorentz, and the inverse particle size of aerosol is obtained in the range of 0.5-3 渭 mm, the error is less than 11.3. The double optical feedback effect in laser self-mixing effect is described. The source and influencing factors of double optical feedback effect are analyzed by simulation and experiment. The theoretical and experimental results show that the double optical feedback effect in the laser self-mixing technique is caused by the two reflections in the external cavity of the laser output laser. The ratio of effective intensity and effective phase difference of two times reflected light is an important factor influencing the degree of double optical feedback effect. A single channel optical fiber system based on the angle and amplitude synchronization measurement of laser self-mixing effect is built. In the angle range of 0.990 掳-1.029 掳and the vibration range of 0-3000mVpp, the error of angle and vibration measurement is better than 12.1% and 1.00% respectively, and the measurement accuracy is 387.5 nm.5. A single-channel optical fiber system based on the synchronous measurement of the velocity and displacement of laser self-mixing effect is built by using the triangle-wave modulation scheme. The effects of the amplitude frequency and asymmetry of the triangular wave on the experimental signal are analyzed and the suitable modulation signal is selected. In the range of velocity of 0.016-0.47m/s and displacement of 1-23mmm, the error of velocity and displacement is better than 5.3 and 9.8.6respectively. A two-channel optical fiber velocimetry system based on laser self-mixing technology is set up, and the synchronous measurement of two channel velocities is realized. When the incident angle is 45 掳, the error of velocity measurement of the two channels is 7.3% and 8.6%, respectively. The measurement error can be reduced to 5.2% and 6.8% respectively by symmetrical and vertical incident light velocimetry.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN24

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