Precision interferometric measurement of optical flat using wavelength tuning Fizeau interferometer

摘要

Wavelength-tuning interferometry has been widely used for measuring the thickness variation of optical devices used inthe semiconductor industry. However, in wavelength-tuning interferometry, the nonlinearity of phase shift causes aspatially uniform error in the calculated phase distribution. In this study, the spatially uniform error is formulated usingTaylor series. A new 9-sample phase-shifting algorithm is proposed, with which the uniform spatial phase error can beeliminated. Finally, optical-thickness variation of transparent plate is measured using the proposed algorithm andwavelength-tuning Fizeau interferometer.