Differential Interference Contrast

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.

Review Articles

de Sénarmont Bias Retardation in DIC Microscopy

DIC with a fixed Nomarski prism and a simple de Sénarmont compensator.
de Sénarmont DIC Microscope Configuration

de Sénarmont compensators offer more accuracy for introduction of bias retardation.

Reflected Light DIC Microscopy

Examination of highly reflective specimens in DIC microscopy with epi-illumination.
Specimen Contrast in Optical Microscopy

Using phase-related optical techniques to increase specimen contrast.

Interactive Tutorials

Bias Retardation Effects on Specimen Contrast

Explore the effects of varying bias retardation on specimen contrast.
Comparison of Phase Contrast & DIC Microscopy

Examples of the same specimen viewed in either phase contrast or DIC.
Nomarski Prism Action in Polarized Light

Variations in prism geometry yield unique interference patterns in polarized light.
Optical Sectioning in Reflected Light DIC

Optical sectioning of reflected light specimens (semiconductors).