Differential interference contrast microscopy

    Differential interference contrast microscopy also known as Nomarski interference contrast (NIC) or Nomarski microscopy, is widely used to create contrast in unstained transparent specimens and is applied in materials science and biological researches.

    Based on the interference principle, DIC microscopy makes it possible to determine the optical density of the specimen and thus to see the details invisible to the human eye. The relatively intricate optical system enables to create a black-and-white picture of the sample on a gray background.

    The principle of this method is that the polarized beam is split by Nomarski prism into two beams that pass through the sample in different optical paths. The length of these optical paths (i.e. the product of the refractive index and the geometrical path length) is different. Subsequently, these beams are interfered at the confluence. It enables to create a three-dimensional relief image that corresponds to the change in the optical density of the sample, emphasizing lines and boundaries.

    The steeper is the gradient of the optical beams – the sharper the image contrast.


∙   MICRO 200 (T) - 01