Differential interference contrast (DIC) microscopy is widely used to observe structure and motion
in unstained, transparent living cells and isolated organelles, producing a monochromatic shadowcast
image of optical phase gradient. Polarized light microscopy (Pol) reveals structural anisotropy
due to form birefringence, intrinsic birefringence, stress birefringence, etc. DIC and Pol
complement each other as, for example, in a live dividing cell, the DIC image will clearly show the
chromosomes while the Pol image will depict the distribution of the birefringent microtubules in the
spindle. Both methods, however, have the same shortcomings: they require the proper orientation of
a specimen in relation to the optical system in order to achieve best results.