Numerical investigation of multi-beam laser heterodyne measurement with ultra-precision for linear expansion coefficient of metal based on oscillating mirror modulation

This paper proposes a novel method of multi-beam laser heterodyne measurement for metal linear expansion coefficient. Based on the Doppler effect and heterodyne technology, the information is loaded of length variation to the frequency difference of the multi-beam laser heterodyne signal by the frequency modulation of the oscillating mirror, this method can obtain many values of length variation caused by temperature variation after the multi-beam laser heterodyne signal demodulation simultaneously. Processing these values by weighted-average, it can obtain length variation accurately, and eventually obtain the value of linear expansion coefficient of metal by the calculation. This novel method is used to simulate measurement for linear expansion coefficient of metal rod under different temperatures by MATLAB, the obtained result shows that the relative measurement error of this method is just 0.4%.     

光束分束比对2μm平衡式相干探测系统信噪比影响的实验研究

给出了平衡式相干探测系统的一般信噪比数学模型,对该数学模型和普通单源相干探测系统的信噪比模型进行了数值仿真对比研究.仿真结果表明,当平衡式相干探测系统中的光电探测器理想匹配时,其系统的信噪比以分束比系数等于0.5呈对称分布;而当光电探测器失配时,系统的最大信噪比所对应的最佳光束分束比发生偏离.最后搭建了2μm平衡式相干...     

Doppler振镜正弦调制多光束激光外差二次谐波测量角度的方法

提出了一种多光束激光外差测微小角度的新方法. 基于激光外差技术和Doppler效应, 通过做简谐振动的Doppler振镜对不同时刻入射光的正弦调制, 把待测角度信息加载到外差信号的频率差中, 经信号解调后可以得到待测角度参数值, 经加权平均处理可以提高待测角度的测量精度. 利用这种新方法, 通过Matlab仿真了平面标准镜不同入射角的模拟结果, 表明该仿真结果的最大相对误差小于0.789677%. 关键词： 角度测量 多光束激光外差 激光Doppler技术 Fourier分析     

多普勒振镜正弦调制多光束激光外差测量玻璃厚度的方法

本文提出了一种多普勒振镜正弦调制多光束激光外差测量玻璃厚度的新方法. 基于激光外差技术和多普勒效应, 通过做简谐振动的多普勒振镜对不同时刻入射光的频率进行正弦调制, 把待测厚度信息加载到外差信号的频率差中, 通过快速傅里叶变换对外差信号解调后可以同时得到多个待测玻璃厚度值, 经加权平均处理可以提高待测厚度的测量精度. 利用这种新方法, 通过MATLAB仿真测量了不同玻璃厚度值, 结果表明：该测量结果的最大相对误差小于0.008%.