纳米位移测量技术是实现高精度纳米制造的基础。激光自混合干涉为精密纳米位移测量提供了一种结构简便、成本低廉，同时测量精度可达纳米量级的精密位移测量方法。区别于传统基于反射镜或散射面为反馈元件的激光自混合干涉测量方案，研究了一种基于平面反射式全息光栅的激光自混合纳米位移测量方法，该方法的位移测量结果以光栅的周期为基准。实验测得了在弱反馈强度条件下的光栅自混合干涉信号，通过阈值设定的方法确定位移方向的反转点，结合反余弦的相位解包裹算法处理光栅自混合信号，获得了对应的位移测量值。最终采用商用激光干涉仪与自组装的光栅自混合干涉仪进行位移测量数据的比对测量，实验结果表明，经过线性修正后，其位移误差不超过0.241%。

The self-mixing interferometry (SMI) technique is an emerging sensing technology in microscale particle classification. However, due to the nature of the SMI effect raised by a microscattering particle, the signal analysis suffers from many problems compared with a macro target, such as lower signal-to-noise ratio (SNR), short transit time, and time-varying modulation strength. Therefore, the particle sizing measurement resolution is much lower than the one in typical displacement measurements. To solve these problems, in this paper, first, a theoretical model of the phase variation of a single-particle SMI signal burst is demonstrated in detail. The relationship between the phase variation and the particle size is investigated, which predicts that phase observation could be another alternative for particle detection. Second, combined with continuous wavelet transform and Hilbert transform, a novel phase-unwrapping algorithm is proposed. This algorithm can implement not only efficient individual burst extraction from the noisy raw signal, but also precise phase calculation for particle sizing. The measurement shows good accuracy over a range from 100 nm to 6 μm with our algorithm, proving that our algorithm enables a simple and reliable quantitative particle characteristics retrieval and analysis methodology for microscale particle detection in biomedical or laser manufacturing fields.

针对传统激光干涉折射率测量精度易受环境扰动，样品用量大等问题，本文提出一种全光纤多重回馈液体折射率测量系统。该系统以光纤光栅激光器作为内腔，以中空光纤作为外腔构成基于封闭式双重外腔激光回馈液体折射率测量系统，并对光纤结构的模式耦合效率、液体折射率测量精度进行了理论分析与计算。实验结果表明，该系统的理论测量精度可达到3.44×10^-5，由于采用了闭合光纤元件一体熔接，因此对热抖动和机械振动表现得更稳定，待测样品不需要匹配，也没有被污染的危险。该系统将微纳器件和流体力学相结合，可构造出物理、化学、生物等科研所需的特殊研究环境，具有快速、高效，样品取样少等优点。

利用激光自混合干涉测振技术，研究一种非接触式声共振探雷方法。在论述激光自混合测振技术原理的基础上，以69式防坦克塑壳地雷、72式防坦克金属地雷、58式防步兵橡胶地雷和砖块作为测量对象，构建其声学特征测量实验系统，设计并搭建地雷在埋设情况下的探测实验系统，利用激光自混合测振技术研究不同类型埋设地雷及同一地雷在不同埋深和土壤条件下的声振特性。实验结果显示，地雷在外界激励下表现出独特的多模态振动特性，在不同埋设条件下表现出不同的声振特征，地表振动强度随着深度的增加和土壤孔隙度的减小而减小，而对土壤湿度的变化不明显。利用激光自混合测振技术可进行地雷振动特征的非接触式检测，埋设地雷的声振特征不同于砖块等干扰物，与地雷的类型及埋设条件有关。

An improved self-mixing grating interferometer based on the Littrow structure has been proposed in this Letter to measure displacement. The grating is integrated inside the interferometer to reduce the impact on the vibration parameters of the object caused by the grating attached to the vibrating object. The +1st diffracted light returns to the laser cavity after being reflected by the target object, and self-mixing interference occurs. The displacement can be reconstructed by processing the self-mixing signals. The feasibility of the proposed interferometer is demonstrated by experimental measurements, and results show that it can achieve micro displacement measurement with the maximum absolute errors of less than 50 nm.