Abstract

This paper presents a new method for radius of curvature measurement by interferometers. The radius measurement is carried out directly in the interferometer confocal position without the need for a specific hardware and thus allows us to measure a much more diverse range of optical surfaces than standard methods. The method is based on measuring a number of phase maps and displacements at several steps through the confocal null position. Radius of curvature is then computed as the tangent slope of the measured defocus–displacement pair values in the confocal position. A relative accuracy of the method is approximately 0.05%, which makes the method suitable for a vast number of applications. Results of the method are verified using standard confocal cat’s eye technique.

© 2021 Optical Society of America

Interferometric measurement of the radius of curvature based on axial displacement from a confocal position and corresponding defocus wavefront

Yiming Liu, Jinpeng Li, Yao Hu, Shaohui Zhang, Zichen Wang, Chuheng Xu, Shuai Yang, Weiqian Zhao, and Qun Hao
Appl. Opt. 62(20) 5443-5451 (2023)

Absolute interferometry for fast and precise radius measurement

Jan Kredba, Pavel Psota, Marek Stašík, Vít Lédl, Lukáš Veselý, and Jakub Nečásek
Opt. Express 29(8) 12531-12542 (2021)

Radius measurement by laser confocal technology

Jiamiao Yang, Lirong Qiu, Weiqian Zhao, Xin Zhang, and Xu Wang
Appl. Opt. 53(13) 2860-2865 (2014)

Laser differential confocal radius measurement system

Ruoduan Sun, Lirong Qiu, Jiamiao Yang, and Weiqian Zhao
Appl. Opt. 51(26) 6275-6281 (2012)

Laser confocal radius measurement method for unpolished spheres

Xu Wang, Weiqian Zhao, Lirong Qiu, Shuai Yang, and Zhongyu Wang
Appl. Opt. 55(17) 4558-4563 (2016)