differential interference contrast (DIC)

A contrasting technique that utilizes illumination with polarized light that has been sheared into parallel ordinary and extraordinary rays, with differences in optical path length between these rays manifesting as constructive and destructive interference once recombined, creating contrast.

Related MicroscopyU Article

DIC

An excellent mechanism for rendering contrast in transparent specimens, differential interference contrast (DIC) microscopy is a beam-shearing interference system in which the reference beam is sheared by a minuscule amount, generally somewhat less than the diameter of an Airy disk. The technique produces a monochromatic shadow-cast image that effectively displays the gradient of optical paths for both high and low spatial frequencies present in the specimen. Those regions of the specimen where the optical paths increase along a reference direction appear brighter (or darker), while regions where the path differences decrease appear in reverse contrast. As the gradient of optical path difference grows steeper, image contrast is dramatically increased.