基于激光回馈效应的应力测量系统研究

Study on stress measurement system based on laser feedback effect

玻璃材料的内应力直接影响玻璃零件加工质量和光学器件使用寿命,在航空航天、精密光学系统,精密加工等领域受到高度重视,高灵敏度,大测量范围的应力检测技术已经成为当前的研究热点。本文提出一种基于激光回馈效应的应力测量方法。激光回馈系统由激光器和外部反射镜构成,待测样品放置在回馈外腔中。由于应力引起的双折射效应,带有应力的样品使外腔分裂为两个“物理长度”,不同的外腔长决定了不同偏振方向的回馈光相位,通过提取相位差信息,可获得应力的大小。从理论上分析了回馈系统中激光器的输出光在正交方向的相位与外腔应力双折射的关系;通过傅里叶变换的方式得到双折射外腔激光回馈系统光强调谐曲线的相位信息;最后,采用激光回馈系统对不同的飞机座舱有机玻璃样品内应力进行了测量,并给出测量结果。该方法具有结构简单、精度高的优势,并且具有应用于玻璃材料生产线、改进制备工艺的潜力。

The internal stress of the glass material directly affects the processing quality of the glass parts and the service life of the optical components,and is highly valued in the fields of aerospace,precision optical systems,precision machining,etc.High sensitivity,large measurement range of stress detection technology has become a hot research topic.In this paper,a stress measurement method based on laser feedback effect is proposed.The laser feedback system consists of a laser and an external mirror,and the sample to be tested is placed in the feedback cavity.Due to the birefringence effect caused by stress,the stressed sample splits the external cavity into two"physical lengths",and the different external cavity lengths determine the phase of the feedback light in different polarization directions.The feedback light of different phases modulates the internal gain of the laser,so that the output light of the laser produces a phase difference in the orthogonal direction.By extracting the phase difference information,the magnitude of the stress can be obtained.The relationship between the phase of the output light of the laser in the feedback direction and the stress birefringence of the external cavity is analyzed theoretically.The phase information of the intensity tuning curve of the birefringent external cavity laser feedback system is obtained by Fourier transform.Finally,the internal stress of different aircraft cockpit glass samples was measured by laser feedback system,and the measurement results were given.The method has the advantages of simple structure and high precision,and has the potential to be applied to a glass material production line and to improve the preparation process.