The aim of this study is to model edge enhancement effect in purely phase samples. A self compensating interferometer
similar to Sagnac’s, employed with a polarizing beam splitter where two counter propagating orthogonally polarized
mutually coherent beams are modulated by the phase shifts introduced by a phase sample. An afocal imaging system is
used to image the phase sample on the CCD so that one of the images is slightly defocused. Real-time subtraction of two
images results in intensity modulation of phase interfaces.