3 Product and Functional Description | 3.4 Microscopy and Contrast Methods
ZEISS
3.4.10 Reflected Light TIC Microscopy
The reflected light TIC method (Micro-interferometry; TIC = Total Interference Contrast in the cir-
cular polarized light) is used in imaging and measuring sample structures that exist in different az-
imuths.
Evaluation of the measured values
Fig. 36: Interference stripes
The values
a
(distance between interference stripes) and
b
(offset of the interference stripes along
the step) are determined with the aid of an eyepiece reticle micrometer or with a micrometer eye-
piece.
If working with white light (without an interference filter), set λ = 550 nm. When interference fil-
ters are used, it is important to apply the focal point of their wave lengths.
The measured path difference depends on the aperture and increases with the illumination aper-
ture.
The step height SH is determined with the following formula:
Where
SH = step height in nm
n = refractive index of the environment, mostly air (n = 1)
Δ = phase difference
a = distance between interference stripes
b = offset of the interference stripes along the step
λ = wave length of the illumination in nm
The following correction values must be considered depending on the objective used:
Objective
Correction factor k
5x/0.15
1.0057
10x/0.25
1.0161
10x/0.30
1.0236
20x/0.4
1.0436
20x/0.50 and 50x/0.75
1.0718
50x/0.60
1.1111
50x/0.75 and 100x/0.75
1.2038
50x/0.80
1.2500
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Instruction Manual ZEISS Axioscope 5, Axioscope 5/7 MAT | en-US | Rev. 13 | 430035-7344-001