Additive Compensation
The eyepiece introduce aberrations on purpose to cancel the objective’s
Subtractive Compensation
The eyepiece avoids adding abberations and instead reduced residual ones
Isotropism
When a substance or material has identical light properties in all directions
What substances are Isotropic?
(hint: 3)
Glass, fiberglass, salt
How do you determine Isotropism?
By using Polarized Light Microscopy (PLM) and seeing if it is completely black (extinct) in all directions when the stage is rotated
Anisotropism
When a specimen exhibits different optical properties in different directions
What substances are Anisotropic?
Most substances in nature
Polyester, nylon, acetates, synthetic fibers, quartz grain, corn starch,
and potato starch
How to determine Anisotropism
The specimen is visible in certain directions when the stage is rotated
Uniaxial Indicatrix
Uniaxial Interference Figure
(Under microscope)
What does the roman cross represent on a Uniaxial Interference Figure?
Isogyres (points of extinction)
What direction does epsilon (ϵ) vibrate?
Laterally
If epsilon (ϵ) is fast….
the optic sign is positive (+)
If epsilon (ϵ) is slow….
the optic sign is negative (-)
If blue is in the 1st and 3rd quadrant, the optic sign is…
is positive (epsilon is fast)
If yellow is in the 1st and 3rd quadrant, the optic sign is…
Negative (epsilon is slow)
If the roman cross is magenta, this indiciates that…
A full wave plate is in
Isochromes
The colored circles that indicate the number of orders
Biaxial Interference Figure
Contains isogyres (roman cross/points of extinction) that when rotated, the hyperbolas switch quadrants
Where is the Melatope on the Biaxial Interference Figure?
