Fizeau interferometer is widely used to test the surface deformation of the optical lens surface profile. However, in some measurement circumstances the common path condition of the Fizeau configuration does not hold. For example, the subaperture scanning interferometry of asphere or the non-null aspherical element testing has dense fringe spacing. Systematic aberrations of non-null testing are introduced into the measurement wavefront with the high wavefront slope of the returning beam. We propose to use a two-dimension scanning device to drive a test ball to different fields of the Fizeau interferometer for the the interference phase at each field. By least square fitting the measurement, we can get the double Zernike polynomial coefficients representing the field dependent aberrations in the interferometer system. According to the coefficients, the off-axis aberrations in the interferometer can be identified

Date Published: 18 August 2014
PDF: 8 pages
Proc. SPIE 9203, Interferometry XVII: Techniques and Analysis, 92030I (18 August 2014); doi: 10.1117/12.2061493

Published in SPIE Proceedings Vol. 9203:
Interferometry XVII: Techniques and Analysis
Katherine Creath; Jan Burke; Joanna Schmit, Editor(s)