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How does Nomarski microscopy work?

How does Nomarski microscopy work?

Nomarski microscopy, also known as Nomarski interference contrast (NIC) is an optical microscopy technique used to enhance the contrast in unstained transparent samples. It works on the principle of interferometry to gain information about the optical path length of the sample to see otherwise invisible features.

What is the function of DIC prism?

Differential interference contrast imaging can be used in conjunction with fluorescence microscopy to provide a better fluorescence image and to pinpoint specific areas on a specimen before switching to the fluorescence mode to further examine the object.

How does a DIC microscope work?

DIC works by separating a polarized light source into two orthogonally polarized mutually coherent parts which are spatially displaced (sheared) at the sample plane, and recombined before observation.

What is the difference between phase contrast and DIC?

In both cases, contrast in the images obtained from DIC is largely dependent upon the orientation of the specimen with respect to the shear axis of the microscope, while the phase contrast image features are independent of specimen rotation around the microscope optical axis.

Why is a DIC micrograph brightly colored?

In DIC, light emitted from the source is linearly polarised by passing through a polariser. The light then travels to the eyepiece or camera, where a DIC image with differences in intensity and colour, can be seen. A diagram showing the journey of light in DIC.

How do I adjust my DIC?

Turn the adjustment knob on the DIC slider until a black band extends diagonally across the objective back focal plane. Replace the eyepiece, and make any final adjustment of the slider to give best DIC contrast. The DIC image has a 3-D quality, as if illuminated by a uni-directional angled light source.

How do you perform a DIC?

Place the polarizer into the light path by swinging the plastic filter holder located above the condenser into place. The polarizer needs to be rotated until it is orientated at 90O with respect to the analyzer. To this, look through the eyepieces with the lamp on and rotate the polarizer using its adjustment lever.

What is Kohler illumination and why do we use it?

Köhler illumination provides a uniformly illuminated, bright field of view, which is important when using an uneven light source, like a coiled tungsten filament. At the end of the 19th century, microscopists used sunlight or oil lamps to illuminate their specimens, and very slow film to photograph them.

What are some advantages of phase contrast and DIC microscopy?

A primary advantage of differential interference contrast over phase contrast is the ability to utilize the instrument at full numerical aperture without the masking effects of phase plates or condenser annuli, which severely restrict the size of condenser and objective apertures.