本文讨论激光外差干涉技术测量表面粗糙度仪器的工作原理。作者利用两个声光调制器产生差频光,解调拍频信号并进行鉴相处理,精确测量表面粗糙度。文中还讨论了设计研制的表面粗糙度外差干涉仪的具体技术问题,对不同样品及加工表面进行实测,并与传统触针测试方法、干涉显微镜所得到的结果进行了比对,理论分析与实验结果一致:仪器灵敏度为10(?),测量精度10nm。 This article discusses the principle of laser heterodyne interferometry for measuring surface roughness instrumentation. The author uses two acousto-optic modulators to generate difference frequency light, demodulates beat signals and performs phase discrimination to accurately measure surface roughness. The paper also discussed the specific technical problems of the designed surface roughness heterodyne interferometer, measured the different samples and the machined surface, and compared with the traditional stylus test method, the results obtained by the interference microscope, the theoretical analysis and The experimental results are consistent: the instrument sensitivity is 10 (?), The measurement accuracy of 10nm.