提出一种新的基于环形子孔径扫描的锥形镜面形测量方法,该方法可实现大口径、不同锥角的锥形镜面形的通用化测量。使用微动扫描台移动锥形镜,同时测量待测锥面法线方向若干环带的相位,提取有效像素并通过插值拼接得到被测锥形镜的面形。该方法可实现锥角大于96.4°的锥形镜面形的测量,测量口径可达100 mm以上,理论测量精度达到λ/4 PV(λ为波长;PV为峰谷值)。使用ZYGO公司4英寸(1 inch=2.54 cm)的DynaFiz干涉仪对一个标称角度为140°的凸面锥形镜顶部的面形进行检测,被测样品旋转90°前后的面形检测结果与使用Taylor-Hobson公司LuphoScan轮廓仪检测结果一致,PV值相差0.54 μm,验证了该方法的可行性。

Herein, a novel method for measuring axicon surface based on annular sub-aperture scanning is proposed. This method successfully performs the general measurement of axicon surfaces with a large diameter and different cone angles. A micro-motion scanner is used to move the axicon step by step while the wave measuring interferometer records several ring phases in the normal direction of axicon. The surface is computed by extracting effective pixels and the interpolation-stitching. The proposed method successfully measures an axicon with a cone angle greater than 96.4° and a diameter above 100 mm. Results in the normal direction of the surface are exclusively used, and a theoretical measurement accuracy up to λ/4 PV (λ is wavelength; PV is peak valley) is achieved. In the experiments, the top surface of a convex axicon (with a nominal angle of 140°) is measured by a 4-inch (1 inch=2.54 cm) DynaFiz interferometer of ZYGO company. Two measurements are performed with the axicon rotated at 90°. Both results are in good agreement with the measurement results of the LuphoScan profiler of Taylor-Hobson company, and the difference in PV values is 0.54 μm. These results demonstrate the good feasibility of the proposed method.