计算全息法测量长焦透镜面形和焦距

为了同时对长焦透镜的面形和焦距进行高精度检测，提出在Zygo干涉仪的球面光路中加入一个二元衍射元件作为检测件的计算全息法。 首先对计算全息法检测长焦透镜的面形和焦距进行了理论推导，并给出焦距误差公式。在Zemax中使用在平面基底上制作的二元衍射元件对一个长焦透镜的面形和焦距进行了模拟检测，其中对该长焦透镜面形的干涉检测PV值为0.0034λ，对焦距的检测精度为-0.11%。最后详细分析了两类误差对检测结果的影响，其中光学元件的位置误差影响不超过0.1λ；二元衍射元件的制造误差影响约0.01λ，在具体制造过程中，其径向位置误差和台阶误差可分别在2 μm和5 nm之内。在综合考虑各项误差的情况下，该方法的检测精度仍然可控制在2λ/25之内。

Measurement of optical surface and foci of long focal length lens by CGH

In order to obtain a high testing precision in the measurement of optical surfaces and focal length of a long focal length lens at the same time, the Computer-generated Holograms(CGH) method was presented by adding a diffractive optical element in the spherical optical path. Firstly, the optical surface test formula and the focal length test formula of the long focal length lens were derived, and the error of the focal length test formula was analyzed. In Zemax, the optical surface and focal length of a lens were tested with the CGH, which should be etched on a flat glass substrate, the PV value of the optical surfaces interference pattern is 0.003 4λ, and the test precision of the focal length is -0.11%. Finally, the influences of two errors on the test result were analyzed particularly, and the influence is no more than 0.1λ for the position error of the two optical elements and about 0.01λ for the fabrication error of CGH, where the radial position error is about 2 μm and the step error is about 5 nm. Considering the effects of all test errors, the test precision of the method can be controlled within 2λ/25.