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

• Published in: Chinese physics B Vol. 20; no. 1; pp. 398 - 404
• Main Author: 李彦超 王春晖 曲杨 高龙 丛海芳 杨彦玲 高洁 王邀游
• Format: Journal Article
• Language: English
• Published: IOP Publishing 2011
• Subjects: 光外差测量; 数值研究; 激光外差; 线性膨胀系数; 超精密测量; 金属反射镜
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/20/1/014208

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%.