AxoScanTM System Options and Measurement Solutions

AxoScanTM System Options and Measurement Solutions
Axometrics, Inc.
515 Sparkman Drive
Huntsville, AL 35816
U.S.A.
tel:
fax:
1-256-704-3332
1-256-704-6003
email: [email protected]
web:
www.axometrics.com
AxoScanTM System Options
and Measurement Solutions
AxoScan Mueller matrix polarimeters represent the most advanced
polarization measurement systems available.
This brochure
describes standard system configurations, and a wide variety of
measurements that can be made with the system.
Don’t see the system or solution that you need? Contact an
Axometrics application engineer today to discuss your application.
All statements and technical information related to Axometrics products are believed to be accurate. However, the accuracy or completeness of this information is not guaranteed, and no
responsibility is assumed for any inaccuracies. Axometrics assumes no responsibility for any damages whatsoever associated with the use or application of this product. Axometrics reserves the
right to change the design, specifications, functions, or availability for sale of its products, at any time without notice. AxoScan, AxoView, Axometrics, and the Axometrics logo are trademarks of
Axometrics, Inc. ©2004 Axometrics, Inc. all rights reserved.
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Standard AxoScanTM
Systems
Light Sources
Every application has a different light-source
requirement. Axometrics offers several standard
solutions, as well as systems that let you use
your own light source.
The Polarimeter Engine
All standard systems are based around the
AxoScan Polarimeter Engine, the fastest and
most
accurate
complete
polarization
measurement system available.
•
Temperature stabilized laser provides longlife at a single wavelength.
•
Xenon Arc-lamp with scanning
monochromator for spectral measurements
across the visible wavelength range
•
Connectors and integrated collimator for
SMA- or FC-connectorized fibers lets the
user supply nearly any light source
The AxoScan Polarimeter Engine
•
Calibrated systems for the visible spectrum,
near-infrared, and telecom wavelengths
•
Extremely rugged – Ideal for laboratory or
production use
•
Can be held in any orientation
•
Not sensitive to slight misalignments or
vibration
•
Variety of mounting options
•
Tightly-integrated automation solutions
available
•
Turn-key operation
Stabilized Laser
Filtered arc-lamp delivered through
an optical fiber
Mounting Fixtures
FC-connectorized fiber for use with
telecom wavelengths
Several standard mounting fixtures are available
to suit the needs of users in a wide range of
different industries
•
Light-weight extruded
aluminum frame for standalone operation
•
Mounts for horizontal
operation on a standard optics
table
•
Brackets for vertical mounting
on 1.5-inch pillar
A variety of AxoScan mounting fixtures are available for different industries
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AxoViewTM Software Interface
All AxoScan polarimeters ship with the AxoView
software interface pre-installed and ready to use.
•
Simple control of the polarimeter hardware
•
Powerful and intuitive data visualization
•
System can be controlled remotely over RS232 for integration into your automated test
setup
SpectroPolarimeter
Option
Tunable Visible Light Source
•
Long-life Xenon arc lamp and grating
monochromator
•
Tune to any wavelength from 400 to 800 nm
•
5 nm spectral bandwidth
•
Turn-key operation and seamless integration
with the AxoView software interface
•
Measure polarization properties across the
visible spectrum in under five seconds
Advanced visualization tools for interpreting polarization spectra.
Here we see a measurement of a retarder with more than one
wave of retardance.
Advanced Spectral Analysis
AxoScan SpectroPolarimeter integrates a Xenon arc lamp
and scanning monochromator for measurements across the
visible spectrum
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•
Visualization tools for analyzing polarization
properties vs. wavelength
•
Analyze any polarization property
•
Includes routines for determining the true
order of retarders
•
Export data to spreadsheet files
•
Export graphics to JPEG files for inclusion in
reports and presentations
•
Viewer software can be installed on multiple
computers allowing exported data to be
shared between technicians, engineers, and
managers
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Automated XY Table
Option
•
Generate easy-to-understand maps of
parameters such as retardance, fast-axis
orientation, polarizer axis, depolarization,
percent transmission, etc.
•
Flexible software for setting up scan
parameters
•
Measure up to 3 sites per second
•
Standard system handles samples up to 6”
square. Larger scan areas available upon
request
XY scan table option for the AxoScan
Polarimeter
Automated Tip-Tilt
Table Option
LCOS Retro-Reflection
Fixture Option
•
Automated, high-speed filed-of-view testing
for all polarization optics
•
Directly measure retardance magnitude and
orientation in retro-reflection
•
Automatically locate and tilt about both fastand slow-axes
•
XY scan table for mapping cell gap variations
•
Measure retardance vs. voltage
characteristics
•
Advanced data reduction techniques remove
the effect of the non-polarizing beamsplitter
used for the measurement
•
Out-of-plane retardance measurements
•
LCD pre-tilt measurements
Tip-Tilt table option for the AxoScan Polarimeter
LCOS retro-reflection fixture for the AxoScan polarimeter
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Measuring Retarders
and Waveplates
Films and Simple Waveplates
•
•
Measure extremely low retardance, extremely
large retardance, and everything in between
o
Minimum measurable retardance
about values as low as 0.25 nm
(0.15° at 550 nm)
o
Maximum measurable
retardance >6,000 nm
Measure retardance versus wavelength to
determine dispersion relation of material
•
Distinguish between fast- and slow-axes
•
Measure axis orientation to within 0.1°
•
Maps of spatial variation
•
Off-axis / Field-of-view variations
Measured retardance map of a quarter-wave plate. The
retardance is 90° in the center of the plate, but t here is a 15°
variation in retardance across the clear aperture.
Compound Zero-Order and
Achromatic Waveplates
•
Measure optical rotation and elliptical fastaxes due to misaligned plates
•
Fast-axis orientation variations with
wavelength
•
Measure retardance vs. wavelength
characteristics
•
Determine the true retardance order
•
Actively align plates during assembly
Measured retardance of a 10 nm trim plate
Form-Birefringent Waveplates
•
Measure retardance vs. wavelength
characteristic
•
Identify unexpected polarization-dependent
transmission (diattenuation)
If the two plates of a compound zero-order waveplate are not
perfectly aligned during manufacture, the orientation of the fastaxis can vary significantly, as shown in the measurement above.
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Measuring Polarizers
Crystal Polarizers
Circular Polarizers
•
Measure misaligned input and output
polarizer axes due to improper construction
•
Distinguish between left-hand and right-hand
polarizers
•
Measure strong field-of-view variations as a
function of wavelength
•
Determine transmitted polarization state as a
function of wavelength
•
Actively align retarders to polarizers
•
Measure the retardance and axis alignment
of a retarder in a complete circular polarizer
Dichroic Polarizers
•
Performance vs. wavelength
o
Max and Min transmittance
o
Contrast ratio
o
Polarizer Efficiency
•
Field-of-view testing
•
Measure transmission axis orientation to
within 0.1°
•
Spatial variations in transmission axis
orientation
Measured output polarization state from the high-quality circular
polarizer (left-handed). The polarization state is shown
graphically on the Poincaré sphere.
Polarizing Beam Splitters
Measured maximum transmittance (for polarization state launched
along transmission axis) for three different brands of linear
polarizers.
•
Spatial maps of transmitted and reflected
properties
•
Measure variations in polarizer axis due to
stain birefringence
Reflective Polarizers
•
Difference in transmitted and reflected
contrast ratio
•
Polarization axis orientation
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Measuring Optical
Components
Windows
•
Measure strain birefringence in optics before
or after mounting
•
Dynamic variations with temperature and
adhesive curing
A window that glued into a mount exhibited 1.4° of retardance
due to strain birefringence. Heating the part with a heat gun
quickly reduces the strain down to a retardance of less than
0.2°. The retardance returns to 1.4° as th e part cools down
over the course of an hour.
Mounting a BK7 window with a set-screw induces very large
amounts of strain birefringence. In this XY map, we see
retardance values as large as 22° at the contact po int
Depolarizers
C-Plates
•
Measure which polarization states are
depolarized and which are not
•
Measure the on-axis retardance of c-plates
due to misalignment of the optic axis
•
Max, min, and average degree of polarization
•
Identify the true orientation of the optic axis
•
Identify causes of depolarization
•
Locate the optic axis in z-cut LiNbO3 devices
A PET film with more than 10 waves of retardance can partially
depolarize a beam with a 5 nm FWHM spectral bandwidth.
AxoView provides tools for visualizing depolarization effects.
A z-cut LiNbO3 device should have no retardance on-axis. Here,
we measured 20° of retardance. Tilting the sample by 0.5° causes
the beam to refract into the true optic axis of the sample.
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Bandpass Filters
Optical Rotation / Optical
Activity
•
Measure optical activity / optical rotation
•
Characterize magneto-optical devices
•
Calculate sugar or alcohol concentrations
•
Measure retardance and polarization
dependent loss of filters used an non-normal
incidence
•
Retardance due to strain birefringence
Circular retardance and optical rotation are two names for
the same effect. Here, we measured the optical rotation (in
degrees) of an organic sample (approx. 17 mm or corn
syrup) as a function of optical wavelength.
Beamsplitters and prisms
•
Measure retardance resulting from totalinternal-reflection within prisms
•
Measure s– and p–reflectances and
transmittances
•
Characterize retardance due to propagation
through thin-films at non-normal incidence
A mounted 636 nm bandpass exhibits significant retardance
at normal incidence., likely due to strain birefringence.
Notice that the retardance vs. wavelength curve is
significantly more complex than the 1/λ characteristic typical
of strain birefringence in homogenous materials.
Non-polarizing beamsplitter cubes frequently exhibit
retardance in transmission. Here we show an XY map of
retardance, exhibiting significant variations in retardance.
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Measuring Display
Components
LCOS Panels
•
Make measurements in direct retro-reflection
•
Measure strain birefringence in unfilled cells
•
Directly measure cell retardance
•
Measure retardance vs. voltage
characteristics
•
Map spatial variation in cell gap
o
variation in retardance
o
variation in fast-axis orientation
Measured retardance variation of an LCOS device at 0V.
The 41° of retardance variation is due to variation s in cell gap
across the device.
LCD Panels
•
Complete characterization of any cell mode
•
Direct retardance and eigenmode
measurement
•
Calculate cell-gap, twist angle and pretilt
Biaxial Films
•
Characterize field-of-view enhancing films
•
Accurate fast-axis orientation measurement
•
Measure R0, Rth, and β
•
3D refractive index ellipse
•
Automatically tilt about fast- and slow-axis
High speed measurements of all critical parameters of biaxial films and other
field-of-view enhancing technologies.
Measured eigenmodes (top) and retardance (bottom) of an
STN LCD cell. From these measurements, an inversion
algorithm is used to calculate cell gap = 5.8 µm and
twist angle = 120°.
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Measuring Fiber-Optic
Components and
Waveguides
Optical Source Options
•
Axometrics-supplied single wavelength laser
•
User-supplied source delivered to the
polarimeter via FC-connectorized fiber
o
tunable laser source
o
super-luminescent diode
o
broadband
An FC receptacle and collimator lets you use your
existing optical source. The AxoScan is compatible with
a wide range of sources, including lasers, TLS, SLD,
ASE sources, etc.
Fiber-Coupled Measurements
•
Applications
•
Characterize polarization controllers
•
Measure PMD and PDL
o
differential group delay
o
principal state of polarization
•
Full Mueller matrix measurement allows
determination of high-order PMD
•
Depolarization effects
•
PM fiber alignment
o
Exceptional flexibility for the R&D
environments
•
Measure crystals prior to integration into fiber
devices
•
Launch a free-space beam into a waveguide
or fiber device
FC ports with integrated
collimators
Using a fiber-coupled AxoScan to characterize a WDM filter
Free Space Measurements
•
Adapters are available for directly coupling
the AxoScan heads to fiber-coupled devices
Using a free-space AxoScan to characterize a waveguide
device. The output beam from the polarization state generator
has been launched into the DUT, and the output has been
collimated for measurement by the polarization state analyzer.
Measurement of second-order PMD. In this case the
DGD remains nearly constant with wavelength while the
PSP’s trace out an arc on the Poincaré sphere.
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