Polarization Microscopy - Biomedical Optical Phase Microscopy and Nanoscopy - page 320

Figure 15.10
(A) LC-PolScope image of a thin, polycrystalline calcite film of uniform thickness (300 nm). In this
false-color image, hue represents the orientation of the slow axis and brightness is proportional to
the retardance (see inset). Each crystalline domain has nearly uniform hue and brightness, due to
the uniform birefringence of each domain. (B) The same sample area imaged with the LC-
PolScope with a micro lens array in front of the camera. Each small disk represents a conoscopic
image that is projected by a single micro lens. Each micro lens captures rays that traversed a small
sample region. The white frame in (A and B) identifies a disk in (B) and the corresponding sample
region in (A). The framed disk image has a black center that is surrounded by a bright ring of
changing color. Such a conoscopic interference figure is compatible with the fact that the thin
film is made of calcite that has a uniaxial negatively birefringent crystal structure. In the black
crystal domain, the optic axis of calcite is oriented parallel to the microscope axis, while in other
domains, the optic axis is tilted away from the microscopic axis. The colors of the different
domains indicate the azimuth orientation of the tilt angle. Both images in (A and B) were
recorded using a 63 /1.4NA objective lens. The micro lens array has a pitch of 2 μ m in object

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space. For more details see Ref. [33] .

rotate relative to the septin molecule. When septin was assembled into an ordered
structure, a consistent orientation of the GFP dipoles was detected throughout the structure.

With this chapter, I intended to give a short survey of traditional and modern approaches to
polarized light microscopy and its biomedical applications. I believe, with current
instrumentation, we have only scratched the surface of the potential of polarized light
microscopy, and I look forward to many more advances that will come with combining
hardware components and software tools to decipher ever finer detail that will help reveal
the structural basis of cell function.