光ファイバからの点光源回折球面波を計測の絶対基準とした位相シフト光干渉計の開発

概要

論文の詳細を見る
This paper describes a novel phase-shifting point diffraction interferometer (PS-PDI) that employs 2 fiber-optic point sources, as a tool for measuring surfaces for SOR and EUV mirrors with sub-nanometer accuracy using visible light optics. In conventional interferometry, the figure accuracy of the reference surface determines the measurement accuracy. We therefore need an absolute reference surface with sub-nanometer accuracy. One of the qualified surfaces is a spherical wavefront which comes from point light source. The proposed PS-PDI system uses 2 single-mode optical fibers as point light sources. The system is applied to the measurement of a commercial spherical concave mirror with 500 mm in radius of curvature and 30 mm in diameter. The repeatability of measurement for the mirror is estimated to be about 3 nm in peak-to-valley value at the wavelength of 632.8 nm in He-Ne-laser.
公益社団法人精密工学会の論文
2003-05-05