OPERATION
Axiolab 5
Illumination and contrast methods in transmitted light
ZEISS
05/2019
430037-7444-001
103
4.2.5.3
Determining the polarization direction n
γ
’
(1) Application
The determination of the polarization direction of n
γ
or n
γ
'
respectively (polarization direction with the
absolute or relative largest index of refraction) and n
α
or n
α
'
respectively (polarization direction with the
absolute or relative smallest index of refraction) relative to the morphological directions, e.g. of crystal
surfaces, crystal needles or fibers, provide an important signature of the material. This method is also
used in the diagnosis of bio-crystals (e.g. gout and pseudo-gout).
Fig. 4-14
Determining the polarization direction n
γ
'
using a synthetic fiber as an example
(2) Equipment configuration for Axiolab for conoscopy
−
Eyepiece with crossline reticle
−
Strain-free objectives
−
Pol rotary stage (Fig. 4-13/
1
)
−
Polarizer D (rotatable or fixed)
−
Lambda or lambda/4 compensator as required
−
Pol adjustment tool sample for polarization microscope (453679-0000-000)
(3) Configure the microscope
•
Configure the microscope as for transmitted light brightfield microscopy (see section 4.2.1 (3)), taking
care to ensure the correct inter-pupillary distance in the binocular tube (see section 4.1.1).
•
Center the Pol rotary stage (Fig. 4-7/
1
) and objectives (see sections 3.1.7.5 and 3.1.7.6).
•
Swivel the polarizer (Fig. 4-7/
3
) into the beam path and, if it is rotatable, position it at 0°.
•
Insert the analyzer slider into the beam path and bring it into a crossed position using the setting
wheel. The field of view will appear dark due to the crossed polarizers.
•
Place the Pol adjustment tool sample on the microscope stage and rotate it until the sample appears
dark.
•
Remove the analyzer slider from the beam path and align the reticle along the split cracks of the
sample.
