Here, we present a triple illumination phase interferometer to have a more flexible unwrapping measurement range for single shot optical unwrapping. Three beams of this interferometer illuminate a sample at different incident angles, three phases of the different incident angles are simultaneously recorded using three spatial frequencies. The different direction phases can be used for dual illumination optical unwrapping; as a result, the phase can be unwrapped by more than one measurement range. The feasibility of this technique is demonstrated by measuring a stepped object with heights of 150 and 660 μm. The smaller stepped phase is unwrapped by two measurement range; however, the phase of larger step is wrapped for only one of the measurement range.

Date Published: 13 March 2015
PDF: 6 pages
Proc. SPIE 9369, Photonic Instrumentation Engineering II, 93690W (13 March 2015); doi: 10.1117/12.2079536

Published in SPIE Proceedings Vol. 9369:
Photonic Instrumentation Engineering II
Yakov G. Soskind; Craig Olson, Editor(s)