Differential interference contrast microscopy, also known as DIC microscopy or Nomarski microscopy, is an advanced optical microscopy technique used to visualize and examine transparent biological specimens in exceptional detail. It provides high-resolution, three-dimensional images by enhancing the contrast and giving a pseudo-three-dimensional appearance to the specimen.
DIC microscopy utilizes the interference of two light beams passing through different regions of the specimen, generating an optical effect called shearing interference. This technique makes it possible to visualize fine structural details, such as transparent organelles, without the need for staining or fluorescent labeling.
The basic setup of DIC microscopy involves a specialized prism placed in the light path, creating a shift in the phase between the two beams. This phase shift is captured by a differential image analyzer and converted into a contrast image, providing clear distinctions between different components of the specimen. It highlights variations in refractive index, thickness, and density, as well as subtle changes in the topography of the specimen.
Differential interference contrast microscopy is highly valued in biological and medical research, as it enables the study of live cells and dynamic processes, such as cell motility and division, in real-time. Moreover, it offers advantages over other microscopy techniques by providing excellent optical sectioning, reduced halos and other image artifacts, and enhanced visualization of structures that are difficult to observe using traditional brightfield microscopy.
