Accurate Measurement of Surface Irregularities for a Standard Sphere Using Fizeau Laser Interferometer
Ali, A., Amer, M., Nada, N. (2023). Accurate Measurement of Surface Irregularities for a Standard Sphere Using Fizeau Laser Interferometer. EKB Journal Management System, (), -. doi: 10.21608/jsrs.2023.220756.1112
Ahmed Ali; Mohamed Amer; Nadra Nada. "Accurate Measurement of Surface Irregularities for a Standard Sphere Using Fizeau Laser Interferometer". EKB Journal Management System, , , 2023, -. doi: 10.21608/jsrs.2023.220756.1112
Ali, A., Amer, M., Nada, N. (2023). 'Accurate Measurement of Surface Irregularities for a Standard Sphere Using Fizeau Laser Interferometer', EKB Journal Management System, (), pp. -. doi: 10.21608/jsrs.2023.220756.1112
Ali, A., Amer, M., Nada, N. Accurate Measurement of Surface Irregularities for a Standard Sphere Using Fizeau Laser Interferometer. EKB Journal Management System, 2023; (): -. doi: 10.21608/jsrs.2023.220756.1112

Accurate Measurement of Surface Irregularities for a Standard Sphere Using Fizeau Laser Interferometer

Journal of Scientific Research in Science
Articles in Press, Corrected Proof, Available Online from 26 July 2023  XML
Document Type: Original Article
DOI: 10.21608/jsrs.2023.220756.1112
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Authors
Ahmed Ali email orcid 1; Mohamed Amerorcid 1; Nadra Nadaorcid 2
1Engineering and Surface Metrology Laboratory, National Institute of Standards (NIS), Giza, Egypt
2Physics Department, Faculty of Women for Arts, Science, and Education, Ain Shams University, Cairo, Egypt
Abstract
Spherical surfaces are essential components in optical systems for different applications. Also, standard ‎spheres are typically employed to calibrate dimensional and mass-measuring instruments. Therefore, ‎measuring and eliminating the surface irregularities of these spheres represents a challenge for modern ‎industries. Surface irregularities can be measured by either the contact method (as stylus profilometers) ‎or the non-contact method (as interferometers). The Fizeau laser interferometer (GPI-XP, Zygo Co.) is ‎typically used to accurately measure surface irregularities for flat surfaces, lenses, and mirrors of 102 mm ‎diameter, and it is not prepared for testing heavy spheres. This work presents a modification for the ‎interferometric system to expand its capability for testing spheres of diameters up to 145 mm and masses ‎up to 2 kg. Also, the modification provides automatic rotation for the tested surfaces (an electric rotating ‎platform) to avoid the disadvantages of manual rotation (a tweezer). At different rotation angles, the ‎measurements are performed on a mass-standard silicon sphere (SiScKg-02-d, PTB Inst.). The average ‎measured value of the surface irregularities is 43.9 nm, with an improved repeatability of 2.8 nm and a ‎minimized measurement uncertainty of ±6.8 nm. The evaluation of the uncertainty budget is also ‎investigated in this study.‎
Keywords
Fizeau; Interferometry; Surface irregularities; Silicon sphere
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