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HYPERION User Manual
Bruker Optik GmbH
Options and Accessories 5
5.4.4
Performing IR spectroscopic analyses using polarized light
Do not use an IR polarizer in combination with a VIS polarizer or vice versa. Polarizer
and analyzer have to be intended for the same spectral range.
Before starting a IR spectroscopic measurement, make sure that there is not any VIS
polarizer in the beam path. Reason: The VIS polarizer contains glass and glass absorbs
light in the mid-infrared region.
For enhanced sample visualization with visible light two polarizers (i.e. a polarizer in
front of the sample and an analyzer behind the sample) are recommended. The first
polarizer produces linearly polarized light. When this light goes through an anisotropic
sample, the direction of polarization may change. The second polarizer can be rotated,
using thumbwheel (D in fig. 5.5), to permit polarized light to pass only in a certain direc-
tion. If the two polarizers are ’crossed’, (i.e. their polarization directions are perpendicu-
lar to each other) an isotropic sample such as liquid will appear black. An anisotropic
sample (e.g. an oriented polymer or many crystalline materials) will appear brightly col-
ored. In transmitted light, a single visible light polarizer can sometimes improve the
image contrast. In reflected light, a polarizer-analyzer pair will produce effects similar to
those obtained in transmitted light if some or all of the light passes through at least one
layer of the sample.
A single IR polarizer can be used to measure the dichroism of micro samples. Each
anisotropic sample has two (or possibly three) independent infrared spectra, depending
on the polarizing direction of the IR light in relation to the optical axis of the material.
Measurements of IR dichroism can be used, for example, to determine the orientation of
polymer fibers.
Summary of Contents for HYPERION
Page 1: ...HYPERION User Manual I 24319 ...
Page 56: ...54 HYPERION User Manual Bruker Optik GmbH Overview 3 ...
Page 148: ...146 HYPERION User Manual Bruker Optik GmbH Repair and Maintenance 6 ...
Page 168: ...166 HYPERION User Manual Bruker Optik GmbH Specifications A ...
Page 172: ...170 HYPERION User Manual Bruker Optik GmbH Measurement parameters B ...
Page 174: ...172 HYPERION User Manual Bruker Optik GmbH Spare parts and consumables C ...
Page 175: ...173 Bruker Optik GmbH HYPERION User Manual D System diagram ...
Page 176: ...174 HYPERION User Manual Bruker Optik GmbH System diagram D ...