Eight-step phase shifting algorithm for broadband light interferometry insensitive to envelop variation and phase shifting error

An eight-step broadband light phase shifting algorithm was proposed for the determination of three dimensional micro textures. The actual phase step was calibrated to eliminate the phase shifting error, from the difference between the phase values of two neighbored sampling of the broadband light interference signal. The microscopic interference fringes with phase shifting error of the oblique SiC flat were analyzed. The standard deviation is 1.646 nm, showing excellent agreement with the result obtained without phase shifting error. The proposed method, insensitive to envelop variation and phase shifting error of the interference signal, is practical and accurate for understanding three dimensional micro textures.