双波长半导体激光自混合干涉纳米位移测量技术研究

Displacement measurement based on laser diode self-mixing interferometry technology has the characteristics of compact structure and easy alignment, which can realize long-distance, real-time and on-line measurement. However, there are two problems limited its applications to precision measurement, such as the low accuracy and poor adaptability to different target. For these two problems, the dual wavelength laser diode is used as sensing element of the laser diode self-mixing interferometer. Principle of dual wavelength laser diode self-mixing interference will be studied, and a theoretical model of displacement measurement based on dual wavelength laser diode self-mixing interference will be established. Laser self-mixing interference nano-displacement measurement system with a wide measurement range, high-precision and low-cost will be developed. Based on the equivalent wavelength theory and single-point dual-wavelength measurement technique, a method to achieve nanometer fringe resolution is studied, and then the displacement reconstruction algorithm based on dual wavelength laser diode is carried out. Based on the synthetic wavelength theory and phase compensation technique a self-mixing signal subdivision method is studied, and then a simple scheme based on the synthetic wavelength self-mixing interferometer is implemented for nanoscale displacement measurement. Combined with speckle principle, the relationship between characteristics of self-mixing signal and the feedback coupling coefficient is explored, and then a common displacement reconstruction algorithm suitable for a wide variety of target surfaces and sensor-target distances is developed to improve the adaptability to the target. Finally, the experimental platform is established to verify the theoretical results. The research results will help to improve the independent innovation capability of low-cost nanoscale measuring instruments in our ultra-precision machining, and are of great significance to promote the development of advanced manufacturing technology.

半导体激光自混合干涉位移测量技术具有结构紧凑和易准直等特点，可实现远距离、实时和在线测量。然而测量精度不够高、对目标的适应性差是制约该技术在精密测量领域推广应用的主要瓶颈。为此，本项目采用双波长半导体激光器作为探测元件，研究双波长半导体自混合干涉原理，建立位移测量理论模型，研制大范围、高精度且低成本的激光自混合干涉纳米位移测量系统。基于等效波长理论和同点双波长测量，研究纳米级条纹分辨率的实现方法，探索双波长半导体激光自混合干涉位移重构算法；基于合成波长理论和相位补偿技术，进行自混合信号细分，研究纳米尺度位移测量技术；结合散斑原理，探索自混合信号特征与光反馈水平参数的函数关系，开展通用的位移重构算法研究，提高对测量目标的适应性；构筑系统实验平台验证理论成果。研究成果有助于提高我国超精密加工中较低价位纳米级测量仪器的自主创新能力，对推动先进制造技术的发展具有重要意义。

半导体激光自混合干涉位移测量技术具有结构紧凑和易准直等特点，可实现远距离、实时和在线测量。然而测量精度不够高、对目标的适应性差是制约该技术在精密测量领域推广应用的主要瓶颈。本项目采用双波长半导体激光器作为探测元件，研究双波长半导体自混合干涉原理，建立了位移测量理论模型，研制大范围、高精度且低成本的激光自混合干涉纳米位移测量系统。基于等效波长理论和同点双波长测量，研究了基于偶次等效波长Fourier变换算法的纳米级条纹分辨率的实现方法，探索双波长半导体激光自混合干涉位移重构算法；基于合成波长理论和相位补偿技术，研究了基于合成波长的外腔相位补偿位移放大技术，实现了信号的细分，探索了纳米尺度位移测量技术；结合散斑原理，探索自混合信号特征与光反馈水平参数的函数关系，研究了多次Hilbert变换算法的正交解调技术、局部最大点检测算法和包络提取Fourier变换算法等算法，提高了对测量目标的适应性；构筑系统实验平台验证了理论成果。研究成果有助于提高我国超精密加工中较低价位纳米级测量仪器的自主创新能力，对推动先进制造技术的发展具有重要意义。