Lensless phase-shifting point diffraction interferometer for spherical mirror measurement. (August 2018)

• Record Type: Journal Article
• Authors: Yang, Zhongming; Dou, Jiantai; Yuan, Qun; Gao, Zhishan
• Is Part Of: Optics and lasers in engineering. Volume 107(2018)
• Page Start: 119
• Page End: 126
• Publication Date: 2018-08
• Subjects: Diffraction -- Interferometry -- Spherical surface -- Metrology; 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.2018.03.022
• Languages: English
• ISSNs: 0143-8166

Abstract

Highlights: A lensless phase-shifting point diffraction interferometer with a tiny pinhole to measure spherical mirror surface figures. The Radon transform is used to determine the distance from the tiny pinhole to the CCD target, which guarantees the accuracy of the diffraction calculations. Our lensless phase-shifting point diffraction interferometer not only retains the higher measurement precision by the ideal reference wavefront, but also overcome the fabrication and mounting limitation of the imaging optics. Abstract: We demonstrate a lensless phase-shifting point diffraction interferometer with a tiny pinhole to measure spherical mirror surface figures. The interferograms used to reconstruct the surface figure are formed without imaging optics. Fresnel diffraction calculations with a coordinate transformation are studied as a means of reconstruction method for wavefront amplitude and phase. The Radon transform is used to determine the distance from the tiny pinhole to the CCD target, which guarantees the accuracy of the diffraction calculations. Our lensless phase-shifting point diffraction interferometer not only retains the higher measurement precision by the ideal reference wavefront, but also overcome the fabrication and mounting limitation of the imaging optics. The simulations and experiments have validated the accuracy and feasibility of the spherical mirror measurement by proposed lensless phase-shifting point diffraction interferometer.