Polarization Microscopy - Biomedical Optical Phase Microscopy and Nanoscopy - page 304

Figure 15.3
The living cell in the center is a primary spermatocyte from the crane fly, Nephrotoma suturalis,
imaged with the LC-PolScope. Brightness is directly proportional to the birefringence of the
specimen, independent of the orientation of the birefringence axis (slow axis). The flattened cell is
suspended in the testicular fluid and its image reveals with great clarity the birefringence of
spindle MTs extending from the chromosomes to the spindle poles and of astral MTs radiating
from the centrosomes located near the spindle poles. The birefringence of other cell organelles,
such as elongated mitochondria, surrounding the spindle like a mantle, and small spherical lipid
droplets, is also evident against the dark background of the cytoplasm. The pole-to-pole distance
is approximately 25 μ m.

articles that discuss various aspects of polarizing microscopy, including practical guides to
using the LC-PolScope [17 21] .

15.2 Traditional Polarized Light Microscopy

Polarized light micrographs often render birefringent objects in beautiful, vivid colors, even
though the objects are transparent and colorless when viewed without polarizers. The colors
of those objects appear only when placing them between crossed (or parallel) polarizers,
revealing the color to be as much a property of the object as it is a property of the method
of observation. The colors originate from interference effects, similar to colors that appear
upon reflection of white light off a thin film of oil floating on water. For a birefringent
object, the hue of the interference color depends on the object's thickness and
birefringence, more specifically on the product of thickness times birefringence, which is