We propose a digital holographic interference analysis method based on 2-step phase-shifting technique for measuring optical surface. The technique using 2-step phase-shifting digital interferometry is more efficient than multi-step phase-shifting techniques because 2-step method has an advantage of the reduced number of interferograms. In this measurement system, 2-step phase-shifting digital interferograms are acquired by moving the reference flat mirror surface which is attached to PZT with phase step of 0 or π/2 in the reference beam path and are recorded on CCD device. The optical interferometry is designed on the basis of polarization characteristics of polarizing beam splitter. Therefore the noise from outside turbulence can be decreased. The proposed 2-step algorithm uses the relative phase difference of the neighbor pixels. Experiment has been carried out on the optical mirror. The measurement of the optical mirror surface topography shows that the result using 2-step algorithm is similar to that of other multi-step algorithms. Thus, the proposed method is expected to be used in nondestructive testing of optical components.

Date Published: 25 January 2008
PDF: 8 pages
Proc. SPIE 6912, Practical Holography XXII: Materials and Applications, 69121B (25 January 2008); doi: 10.1117/12.764362

Published in SPIE Proceedings Vol. 6912:
Practical Holography XXII: Materials and Applications
Hans I. Bjelkhagen; Raymond K. Kostuk, Editor(s)