Differential interference contrast microscopy as a polarimetric instrument

Differential interference contrast (DIC) microscopy is shown to be equivalent to an incomplete Stokes polarimeter capable of probing optical properties of materials on microscopic-length scales. The Mueller matrix for a DIC microscope is calculated for various types of samples, and the polarimetric properties for DIC component parts of a spaceflight microscope are spectrally measured. As a practical application, a measurement of the index mismatch between colloidal particles and a nearly index-matched fluid bath was performed.