能量天平动圈位移的激光干涉测量研究

Laser interferometric displacement measurement of the moving coil in joule balance

为精确测量普朗克常数h,实现能量天平法建立量子质量基准,提出了三轴双频激光外差干涉和折叠式Fabry-Perot(F-P)干涉绝对距离测量相结合的激光干涉测量方法,用于精密测量和定位能量天平装置中沿竖直方向在均匀磁场中运动的互感线圈位移。用三轴双频激光外差干涉精密测量运动线圈的质心位移和姿态,位移测量不确定度为10nm;进而将F-P腔干涉绝对距离测量与外差干涉测量结果进行比对和校准。仿真表明,采用本文方法,当位移测量范围约为30mm时,测量分辨率优于1nm。将该方法运用于真空中线圈位移测量,相对测量不确定度优于1.0×10-9。

In order to accurately measure the Plank constant and realize quantum mass standard by means of joule balance,a laser interferometric displacement measurement system,which consists of three laser heterodyne interferometers and a folded Fabry-Perot（F-P） interferometer using absolute distance measurement,measures the displacement of the mutual inductance coil in joule balance moving along the vertical direction in the uniform and radial magnetic field.The displacement of the center of mass and the gesture of the moving coil are obtained through three laser heterodyne interferometers with less than 10 nm uncertainty,and the designed Fabry-perot interferometer would be applied to compare and calibrate the nonlinearities of one heterodyne interferometer.The simulation results show that this method has the displacement measurement range of about 30 mm and the resolution of less than 1 nm.It will be the potential method achieving the relative uncertainty of 1.0×10-9 for the displacement measurement of the moving coil in a vacuum.