Polarized and Differential Interference Contrast (DIC) Microscopy

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Polarized and Differential Interference Contrast
(DIC) Microscopy
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The term polarized light refers to the
properties of light waves in relation to the
plane in which the waves oscillate. A polarizer
can be thought of as an optical screen in which
very fine slats are made which only allows those
waves whose oscillations coincide with the
orientation of the slats to pass through and to
exclude all waves that oscillate in other planes.
Wavelengths of light moving in the same plane are
said to be coherent
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By using polarizers arranged in orthogonal
fashion all light can be blocked. In such cases
the filters are said to be cross-polar
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Thin slice of granite in polarized showing
orientations and positions of different grains.
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Birefringence of microtubules during cell
division.
The silica spicule spines of pluteus larvae of
most echinoderms are naturally birefringent and
can be easily seen in a polarized microscope.
Mitotic Spindles Striated Muscle (actin and
myosin polymers) Plant Cell Walls (cellulose and
lignins) Some protists with crystalline
structures in their cytoplasm
Fat bodies in epithelial cells containing
droplets of lipoproteins and proteins which can
be seen because of the birefringence of the
lipid, which produces maltese cross
configurations.
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The Wollaston prism splits the entering beam of
polarized light into two beams traveling in
slightly different directions. The Wollaston
prism is composed of two quartz wedges cemented
together, from which emerging light rays vibrate
at 90 degrees relative to each other with a
slight path difference. A different Wollaston
prism is needed for each objective of different
magnification.
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DIC (Nomarski) Image