Opt Express. 2023 Apr 10;31(8):12449-12462. doi: 10.1364/OE.486133.
This paper presents a non-nulling absolute interferometric method for fast and full-area measurement of aspheric surfaces without the necessity of any mechanical movement. Several single frequency laser diodes with some degree of laser tunability are used to achieve an absolute interferometric measurement. The virtual interconnection of three different wavelengths makes it possible to accurately measure the geometrical path difference between the measured aspheric surface and the reference Fizeau surface independently for each pixel of the camera sensor. It is thus possible to measure even in undersampled areas of the high fringe density interferogram. After measuring the geometrical path difference, the retrace error associated with the non-nulling mode of the interferometer is compensated for using a calibrated numerical model (numerical twin) of the interferometer. A height map representing the normal deviation of the aspheric surface from its nominal shape is obtained. The principle of absolute interferometric measurement and numerical error compensation are described in this paper. The method was experimentally verified by measuring an aspheric surface with a measurement uncertainty of λ/20, and the results were in good agreement with the results of a single-point scanning interferometer.
本文提出了一种非零位绝对干涉测量方法，用于快速、全场测量非球面，无需任何机械运动。使用几个具有一定激光可调谐性的单频激光二极管来实现绝对干涉测量。三个不同波长的虚拟互连使得能够独立地为相机传感器的每个像素准确测量被测非球面和参考菲佐面之间的几何光程差。因此，即使在高条纹密度干涉图的欠采样区域也能够进行测量。测量完几何光程差后，使用干涉仪的校准数值模型（数字孪生）来补偿与干涉仪非零位模式相关的回程误差。得到表示非球面相对于其标称形状的法向偏差的高度图。本文描述了绝对干涉测量的原理和数值误差补偿方法。该方法通过测量一个具有 λ/20 测量不确定度的非球面进行了实验验证，结果与单点扫描干涉仪的结果吻合良好。
