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Sensing with Light and Fibers - EO & LasMetr Lab
Professor Dr. Friedemann Mohr
HS Pforzheim University, Electrooptics & Laser Metrology LabBrno, 09.11.2010
Sensing with Light and Optical Fibers
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 2
Overview
1. The fiber gyroscope -a rotation rate sensor for use in avionics: Suppression of unwanted cross-sensitivity from elastooptical interactions
2. Embedded fiber-optic sensingwith fiber Bragg gratings and its use in civil engineering,
3. Polarimetrywith microstructured polarizers, a concept enabling real-time measurement of internal stress in optically transparent media
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 3
Part 1 - The fiber gyroscope -
Suppression of unwanted cross-sensitivity from thermal and elastooptical interactions
Project „EMFASE“ - Industrial Partner: SAGEM Navigation
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 4
Only for reference:
The part on
„The Fibre Gyroscope“ project
is cancelled for BIPOMIP presentation
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 5
Part 2 - Embedded fiber-optic sensing –
Fiber Bragg Gratings (FBGs) and their use for Structural Health Monitoring (SHM) in civil engineering
Project „FOSBA“ - Industrial Partner: Bilfinger Berger
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 6
Only for reference:
The part on the
„Embedded Fibre Optic Sensing“ project
is cancelled for BIPOMIP presentation
4
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 7
Part 3 - Polarimetry with microstructured polarizers
A Sensor Concept enabling Real-Time Measurement of Internal Stress in Optically Transparent Media
Project „BIPOMIP“ -Industrial Partners: ilis Erlangen, CODIXX Magdeburg
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 8
Aim of Polarimetric Measurement and
Basic Arrangement for Measuring Birefringence
Aim:
� Determine optical birefringence in
technical glass-products bypolarization analysis.
� Derive internal stress therefrom byapplying elastooptical equations.
� Improve quality of glass products in manufacturing process
� Reduce energy consumption bybetter process control
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 9
Industrial Arrangement of a Polarimeter
(isis Erlangen)
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 10
Concepts for Spatially-Resolved Polarization Analysis
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 11
Basic Arrangement for Measuring Birefringence
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 12
First, the source is imaged on a spatial filter (a pinhole). A collimating lens follows. The collimated beam is needed in order to assure one-to-one imaging between a point in the model plane and a point in the detector plane. After the collimator a linear polarizer (polarizer) follows. Next, the investigated model is placed. Then another linear polarizer (analyzer) follows. The polarizer and analyzer are
crossed (dark field setup). Finally, the model plane is imaged on a CCD sensor
The basic photo-elastic bench (linear polariscope).
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 13
Strain discs patterns for different loads (load A<B<...<F)
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 14
Dependency of the strain disc pattern (load E) on the
angle between polarizer and applied force (stress).
(Mixing of isoclinics and isochromatics.)
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 15
Manufacturing of Micro Polarizers
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 16
Adjustment of Micro Polarizers and CCD Array
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 17
Good Adjustment of Micro Polarizers and CCD Array
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 18
Bad Adjustment of Micro Polarizers and CCD Array
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 19
Micro Polarizers as Diffractive Optical Elements 1
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 20
Micro Polarizers
as
Diffractive
Optical
Elements 2
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 21
Micro Polarizers as Diffractive Optical Elements 3
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 22
Scattering due to the Particle Structure
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 23
The Real-Time
Polarimeter 1
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 24
The Real-Time Polarimeter 2
Same as a colour versionPolarization image as taken by camera
Calculated retardationafter image processing
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09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 25
Further Steps
� Noise Optimization
� Hardware implementation of some part of the image processing
� Goal: Measurement speed of 20 measurements in one second
09.11.10 Sensing with Light and Fibers - EO & LasMetr Lab 26
Summary
1. The fiber gyroscope -a rotation rate sensor for use in avionics: Suppression of unwanted cross-sensitivity from elastooptical interactions
2. Embedded fiber-optic sensingwith fiber Bragg gratings and its use in civil engineering,
3. Polarimetrywith microstructured polarizers, a concept enabling real-time measurement of internal stress in optically transparent media