SLIDE 1
Finnish-Japanese Workshop on Functional Materials Espoo and Helsinki, Finland 25-25.5.2009
Utsunomiya Univesity Center for Optical Research and Education
SURFACE RELIEF GRATING AND RETARDAGRAPHY:
Center for Optical Research and Education Toyohiko Yatagai
SURFACE RELIEF GRATING AND RETARDAGRAPHY: OPTICAL MANIPULATION OF AZOBENZENE POLYMER FILMS AND ITS APPLICATIONS FILMS AND ITS APPLICATIONS
SLIDE 2 OPTICAL FUNCTIONAL DEVICES USING AZOBENZENE POLYMER FILM
Photoisomerization Photoisomerization
Surface relief grating
Surface relief grating
R t d h di f ti l l i ti d
Retardagraphy: recording of optical polarization and
reconstruction of complex amplitude
Functional devices based on multilayer polymer thin
film film
SLIDE 3 PHOTOINDUCED MASS TRANSPORT N nof b i tion photo me h ni l
Nanofabrication, photo-mechanical
devices
R R
Light Two beam interference
N N R' N N
C f Light or thermal
R'
Trans form Cys form Azobenzene Photoinduced surface relief (PSR) formation P . Rochon et al., Appl. Phys. Lett., 66, 136 (1995)
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POLARIZATION DEPENDENT POLARIZATION DEPENDENT
50 μm 10 μm
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MULTIPLE RECORDING GRATINGS MULTIPLE RECORDING GRATINGS
Orthogonal grating structure Surface relief grating Hexagonal structure Blazed grating structure
SLIDE 6 RELEIF DEPTH CONTROL BY ELECTRIC FIELD
H i Homogenious Illumination or heating
Heating +electric field applied substrate Heater
SLIDE 7
COMPUTER SIMULATION BASED ON VISCOUS FLUID MODEL Navier-Stokes equation
Inertial t Pressure t Outer force term Viscous term term term term term
Continuity equation Continuity equation
u: velocity vector
SLIDE 8
COMPUTER SIMULATION OF MASS TRANSFER COMPUTER SIMULATION OF MASS TRANSFER
Nd:YAG Laser (532 nm) Intensity:50 mW/cm2 :Electric Field :Wave number :Wave number 1 μm
SLIDE 9
SUMMARY IN SURFACE RELIEF GRATING Origin of mass transfer: ・Origin of mass transfer: gradient of light intensity gradient of light pressure surface tension surface tension ・SRG generation is mainly due to electric dipole interaction with outer p electric field.
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PHOTOINDUCED BIREFRINGENCE Opti l to ge medi pol i tion
Optical storage media, polarization
controllable devices
Optical recording technique for th t d f bi f i t bj t
Retardagraphy
the retardance of a birefringent object Liquid crystal spatial light modulator Multivalued phase recording with a single laser beam Large amount information recording Large amount information recording
SLIDE 11
PHOTOTRIGGERED MOLECULAR REORIENTATION
Polarization axis Molecular axis axis trans-azobenzene Absorption Absorption Relaxation cis-azobenzene Absorption
SLIDE 12
PHOTOINDUCED BIREFRINGENCE PHOTOINDUCED BIREFRINGENCE
Irradiation area area Polarization axis Azobenzene-containing material
SLIDE 13
POLARIZATION HOLOGRAPHY: RECORDING
F F
Signal beam (Right-circular pol.) Reference beam (Left-circular pol ) (Left-circular pol.) Azobenzene film
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POLARIZATION HOLOGRAPHY: RECONSTRUCTION
F
Reference beam (Left-circular pol ) 0 order beam (Left-circular pol.) 0 order beam (Left-circular pol.) Polarization hologram +1 order diffracted beam (Right-circular pol.) hologram (Right circular pol.)
SLIDE 15 POLARIZATION HOLOGRAPHY: RECONSTRUCTION
F
(Left circular pol ) Reference beam (Right-circular pol.) (Left-circular pol.)
F
Polarization hologram
F
0 order beam (Right-circular pol ) (Right circular pol.)
SLIDE 16
JONES CALCULUS JONES CALCULUS
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PRINCIPLE OF RECONSTRUCTION PRINCIPLE OF RECONSTRUCTION
SLIDE 18
PRINCIPLE OF RETARDAGRAPHY PRINCIPLE OF RETARDAGRAPHY
y x y x z z 45 degree linear polarization 45 degree-linear polarization x-component y-component Recording Recording laser
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PRINCIPLE OF RETARDAGRAPHY PRINCIPLE OF RETARDAGRAPHY
y y z x z x z Phase difference z Phase difference (Polarization retardance) Elliptical polarization x-component y-component y p Recording laser
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EXPERIMENTAL SETUP EXPERIMENTAL SETUP
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OPTICAL RECORDING BY RATARDAGRAPHY
SLIDE 22 SUMMARY IN RETARDAGRAPY SUMMARY IN RETARDAGRAPY
E l i f l i i h l hi h i i i
Explanation of polarization holographic characteristics in
photoinduced birefringent films
Complex amplitude of signal beam from an object Amplitude: Retardance of photoinduced birefringence Phase: Principal axis of photoinduced birefringence Complex amplitude of signal beam from an object
Application to phase-type optical recording by retardagraphy
Features of retardagraphy Features of retardagraphy
Recording absolute retardance values using a single laser beam High robustness
SLIDE 23 MULTILAYER STRUCTURE BY SIPN COARTING
- R. Katouf, T. Yatagai and S. Umegaki:
Photonics & Nanostructure, 3, 116(2005).
SLIDE 24 MULTILAYER STRUCTURE BY SIPN COARTING
- R. Katouf, T. Yatagai and S. Umegaki:
Photonics & Nanostructure, 3, 116(2005).
SLIDE 25
SUMMARY & PROPOSALS SUMMARY & PROPOSALS
Functional photo material: A b l Azobenzene polumers Photoisomerization Surface relief grating: hologaphy & functional gratings Photo induced bifringence: retardagrapy optical memory & Photo-induced bifringence: retardagrapy, optical memory & polarization devices ( polarization grating for LS devices) Optical multi-layer structure: functional modulator Collaboration: Joensuu University (Design of functional devices)
