Interferometer with a space-variant polarization converter to produce radially and azimuthally polarized beams

An interferometer comprising:

• an optical assembly, configured and operable to produce first and second spatially separated optical fields of incident coherent radiation of substantially the same intensity and different polarizations and to define first and second spatially separated optical paths for propagation of said first and second optical fields thereby allowing interaction between the first optical field and an element affecting a phase thereof in said first optical path, said optical assembly comprising a beam splitter/combiner for combining said first and second optical paths into a combined path at a location downstream of said element with respect to the optical fields' propagation through the interferometer;
• a space-variant polarization converter accommodated in said combined path and being configured and operable to simultaneously apply space-variant polarization conversion to two beams corresponding to combined first and second optical fields having different polarizations and produce radially and azimuthally polarized beams respectively,
• an analyzer downstream of said polarization converter, interaction of the radially and azimuthally polarized beams at the analyzer creating interference fringes corresponding to a spatially varying intensity pattern distribution indicative of a two-dimensional varying phase difference between the first and second optical fields propagating along the first and second optical paths indicative of interaction of said first optical field with said element.