Light microscopy Nomarski contrast

One very productive use of Nomarski contrast is examinatirm of etched surfaces prior to electron microscopy. Here one does not want to coat the specimen, so in looking at an etched disc prior to replication, it is better to put it on some black card (surface to be replicated uppermost) to eliminate much of the scattered and reflected light from below. 

Nomarski microscopy is an examination mode using differential interference contrast (DIC). The images that DIC produces are deceptively three-dimensional with apparent shadows and a relief-like appearance. Nomarski microscopy also uses polarized light with the polarizer and the analyzer arranged as in the polarized light mode. In addition, double quartz prisms ( Wollaston prisms or DIC prisms) are used to split polarized light and generate a phase difference. 

Absorption microscopy is the conventional transmitted-light type. Retardation microscopy includes Nomarski interference-contrast (DIC), phase-contrast and polarization. Reflection microscopy includes darkground. 

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