Nomarski Interference Microscopy

Nomarski interference microscopy, also known as differential interference contrast (DIC) microscopy, is the visual method used for finding the complete lineage of every neuronal cell in the nematode C. elegans.

An extremely useful tool for viewing the constituents in transparent specimens. Light passes through a sample which is made up of parts with differing refractive indices, for example the organs of the C. elegans. The phase of the emitted electromagnetic wave will be changed because of the difference path lengths for the light wave. Light travels faster in regions with a lower refractive index. The visible contrast is then worked out by converting the phase changes of the electromagnetic wave into amplitude changes.


The Nomarski imaging technique emphasizes edges and lines, and is more beneficial when studying living specimens than fluorescence microscopy, which can produce phototoxic effects.                     

                                Image of C. elegans
                    worm with DIC microscopy

                               Image taken from Wikimedia commons. Image source.

References:

Plant Microtechnique and Microscopy, Steven E. Ruzin, 1999, ISBN:0-19-508956-1

Olympus microscopy Resource Centre

University of Wisconsin biophotonics instrumentation laboratory