抑制大型折叠腔结构光斑抖动技术的研究

针对光腔镜盒的真空变形和振动对精密光学系统的影响,分析了传统刚性连接的光学调整架平台以及球关节连接结构在减振降噪设计的不足,从支撑和柔性密封连接的角度,设计了隔离振动和光腔镜盒真空变形的精密光学调整架平台,对应用于大型折叠腔的双层光学调整架平台的动力学特性进行ANSYS仿真,并完成了光斑抖动验证实验。结果显示框架式双层光学调整架平台的第一阶弹性体频率可达到126.5,172.3Hz,很好地满足折叠腔光学调整架平台的使用要求;应用在大型折叠腔,抽真空试验前后He-Ne导引光输出光斑位置无变化,形状变化很小,出光过程中输出抖动角均方根值为3.73″,隔离振动传递效果明显。

Technology research of eliminating beam-spot jitter with large folded cavity

The axis of precise optical systems is sensitive to the mount platforms structural deformation and vibration, and the puny structural deformation and vibration are able to directly affect the optical system stability and light-beam alignment precision. This paper analyzes the vibration and noise reduction design defect of traditional rigid connection and spherical joint connecting structure of optical mount platform. By adjusting the mount platforms support and sealing connection, the design of flexible sealed connection between the amount platform and resonator was brought forward. The modal analysis of the double-layer platform frame was carried out with ANSYS finite element method, the beam spot jitter experiment was completed. The modal analysis showed that the first order modal frequencies of the two platforms were increased to 126.5 Hz and 172.3 Hz after optimization with a large folded-cavity. The design adopted the large folded-cavity was tested with a He-Ne laser, the results show that the near-field beam spots typical position and profile changed punily during the resonator box evacuation, and the far-field beam spot jitter angle approached 3.73 (RMS) during the continuous laser operation.