A novel method for identifying the order of interference using phase-shifting digital holography

In this paper, we introduced amathematical method formeasuring
the optical path length differences (OPDs), which is
suitable for large OPD values where the fringes connections
are difficult to detect. The proposed method is based on varying
the width of the fringes, without changing the wavelength of
the used coherent source. Also, in this work, we discussed the
need for such method in off-axis phase-shifting digital holography.
Low-resolution off-axis holograms failed to detect the
correct interference order. In general, off-axis phase-shifting
digital holography is limited by the resolution of the captured
holograms.Theresults obtained using our proposed technique
were compared to the results obtained using off-axis phaseshifting
digital holograms and conventional two-beam interferometry.
Holograms were given for illustration.