Key Techniques in an Absolute Measurement Method of Spherical Lens

摘要

An absolute measurement method of spherical lens with Fiber Point Diffraction Interferometer (FPDI) was developed. To achieve a high accuracy, several key techniques are discussed such as: short coherence length laser, interferogram collecting, experiment set up, and reconstruction of wave front. Through these techniques an experiment system has been built. The 5-step phase shifting interferograms are collected. The wave front is fitted by Zernike polynomials and reconstructed. The repeated measurement result has a good performance compared to a Zygo GPI interferometer.