Circular carrier squeezing interferometry: Suppressing phase shift error in simultaneous phase-shifting point-diffraction interferometer. (March 2018)

• Record Type: Journal Article
• Authors: Zheng, Donghui; Chen, Lei; Li, Jinpeng; Sun, Qinyuan; Zhu, Wenhua; Anderson, James; Zhao, Jian; Schülzgen, Axel
• Is Part Of: Optics and lasers in engineering. Volume 102(2018)
• Page Start: 136
• Page End: 142
• Publication Date: 2018-03
• Subjects: Circular carrier -- Interferometry -- Point-diffraction -- Phase-shifting; Lasers in engineering -- Periodicals; Optical measurements -- Periodicals; Optics -- Periodicals; Lasers en ingénierie -- Périodiques; Mesures optiques -- Périodiques; Optique -- Périodiques; 621.36605
• DOI: 10.1016/j.optlaseng.2017.11.002
• Languages: English
• ISSNs: 0143-8166

Abstract

Highlights: Circular carrier squeezing interferometry (CCSI) is suitable for some occasions in which CSI is not effective, since tilt is difficult to introduce, for example, phase-shifting point-diffraction interferometers, and also when a specimen with large spherical departure or an on-axis asphere with small aspherical departure is measured. There is no retrace error compared to CSI in which a linear carrier is required, usually tilt the reference mirror, and lead to deviation between reflected light and incident light. The CCSI method is effective for different kinds of error source, such as intensity distortion, and phase shift error generated by phase shifter and vibration in other phase-shifting point-diffraction interferometers. Abstract: Circular carrier squeezing interferometry (CCSI) is proposed and applied to suppress phase shift error in simultaneous phase-shifting point-diffraction interferometer (SPSPDI). By introducing a defocus, four phase-shifting point-diffraction interferograms with circular carrier are acquired, and then converted into linear carrier interferograms by a coordinate transform. Rearranging the transformed interferograms into a spatial-temporal fringe (STF), so the error lobe will be separated from the phase lobe in the Fourier spectrum of the STF, and filtering the phase lobe to calculate the extended phase, when combined with the corresponding inverse coordinate transform, exactly retrieves the initial phase. Both simulations and experiments validate the ability of CCSI to suppress the ripple error generated by the phase shift error. Compared with carrier squeezing interferometry (CSI), CCSI is effective on some occasions in which a linear carrier is difficult to introduce, and with the added benefit of eliminating retrace error.