We discuss a number of differential phase imaging techniques which are particularly suited to implementation in scanning optical microscopy. It is shown that a system using an optical fiber capable of supporting two eigenmodes as a detector has considerable advantage over confocal Nomarski systems.
Tony Wilson, Tony Wilson,
"Differential phase imaging in confocal microscopy", Proc. SPIE 2083, Microscopy, Holography, and Interferometry in Biomedicine, (1 February 1994); doi: 10.1117/12.167430; https://doi.org/10.1117/12.167430