Spatially inhomogeneous phase-modulating interferometry by non-quadrature amplitude modulation

Abstract

A new method to generate inhomogeneous spatial phase variation and phase retrieval is proposed. This method is based under the scheme of three beams forming two Mach-Zehnder interferometers in series, where one arm is considered as the probe beam, while the other two will compose the reference beam where a phase difference within the range of (0,π ) is kept and this remains spatially variable in opposition to the classical PSI method. The generation of phase-shifts is done by on-off nonquadrature amplitude modulation. Although the phase difference between the reference beams are spatially variable having as a consequence that the visibility and phase variations are inhomogeneous, it will be demonstrated that it is still possible to retrieve the phase of the object and also to measure the phase variation. An analytic discussion and experimental results will be shown to sustain the proposed method.