Specifications

Operation
Carl Zeiss Transmitted-light polarization Axiostar plus
3-12 B 40-81 e 12/01
3.5 Using transmitted-light
polarization contrast
3.5.1 General principle
The transmitted-light polarization technique is
used with specimens that change the
polarization state of light. Such specimens, e.g.
crystals, minerals or polymers, are termed as
birefringent. If birefringent substances are
viewed between crossed polarizers (polarizer ⊥
analyzer), they appear bright while their
surrounding remains dark.
1 Polarizer on swivel-out carrier
2 Analyzer
Fig. 3-9 Setting transmitted-light polarization
contrast
Birefringent substances are recognized by the
fact that they display 4 bright and 4 dark
positions between crossed polarizers after
rotation of the specimen around 360°.
Depending on the level of birefringence,
thickness and orientation of the object,
interference colors will occur from gray (usually
in biological objects) to white, yellow, red and
blue. These interference colors can be of 1
st
or
higher order.
3.5.2 Transmitted-light polarization
contrast configuration
– Polarizer, oriented in EAST-WEST direction,
mounted on swivel-out carrier (3-9/1).
– Analyzer, oriented in NORTH-SOUTH
direction (3-9/2).
3.5.3 Setting transmitted-light
polarization contrast
Before starting:
– As described in section 2, the microscope is
ready for operation and switched on
according to section 3.1.
– The microscope must be set for
transmitted-light brightfield, as described in
section 3.2.
Settings:
• Screw NORTH-SOUTH-oriented analyzer
(3-9/2) into the tube (removed from the
stand) from below. NORTH-SOUTH
orientation is available when the marking
on the analyzer is aligned along the
longitudinal axis of the stand.
• Swivel polarizer (3-9/1) into the beam path;
the field of view appears dark because of
the crossed polarizers.