Finnish-Japanese Workshop on Functional MaterialsEspoo and Helsinki, Finland25-25.5.2009
Utsunomiya UnivesityCenter for Optical Research and Education
SURFACE RELIEF GRATING AND RETARDAGRAPHY:
Center for Optical Research and EducationToyohiko Yatagai
SURFACE RELIEF GRATING AND RETARDAGRAPHY: OPTICAL MANIPULATION OF AZOBENZENE POLYMER FILMS AND ITS APPLICATIONSFILMS AND ITS APPLICATIONS
OPTICAL FUNCTIONAL DEVICESUSING 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 filmfilm
PHOTOINDUCED MASS TRANSPORT
N nof b i tion photo me h ni l Nanofabrication, photo-mechanical devices
R
RLightTwo beaminterference
NN
R'
N N
C fLight orthermal
R'
Trans form
Cys form
Azobenzene
Photoinduced surface relief (PSR) formationP. Rochon et al., Appl. Phys. Lett., 66, 136 (1995)
POLARIZATION DEPENDENTPOLARIZATION DEPENDENT
50 μm 10 μm
MULTIPLE RECORDING GRATINGSMULTIPLE RECORDING GRATINGS
Orthogonal grating structureSurface relief grating
Hexagonal structure Blazed grating structure
RELEIF DEPTH CONTROLBY ELECTRIC FIELD
H iHomogeniousIllumination or heating
Heating +electric field applied
substrate
Heater
COMPUTER SIMULATION BASED ON VISCOUS FLUID MODEL
Navier-Stokes equation
Inertialt
Pressuret
Outer forceterm
Viscoustermterm term termterm
Continuity equationContinuity equation u: velocity vector
COMPUTER SIMULATION OF MASS TRANSFERCOMPUTER SIMULATION OF MASS TRANSFER
Nd:YAG Laser(532 nm)
Intensity:50 mW/cm2 :Electric Field
:Wave number:Wave number
1 μm
SUMMARY IN SURFACE RELIEF GRATING
Origin of mass transfer:・Origin of mass transfer:gradient of light intensitygradient of light pressuresurface tensionsurface tension
・SRG generation is mainly due toelectric dipole interaction with outer pelectric field.
PHOTOINDUCED BIREFRINGENCE
Opti l to ge medi pol i tion Optical storage media, polarization controllable devices
Optical recording technique forth t d f bi f i t bj t
Retardagraphythe retardance of a birefringent object
Liquid crystalspatial light modulatorMultivalued phase recordingwith a single laser beam
Large amount information recordingLarge amount information recording
PHOTOTRIGGEREDMOLECULAR REORIENTATION
Polarizationaxis
Molecular axis
axis
trans-azobenzeneAbsorption
AbsorptionRelaxation
cis-azobenzene Absorption
PHOTOINDUCED BIREFRINGENCEPHOTOINDUCED BIREFRINGENCEIrradiationareaarea
Polarization axis
Azobenzene-containing material
POLARIZATION HOLOGRAPHY:RECORDING
FF Signal beam (Right-circular pol.)
Reference beam(Left-circular pol )(Left-circular pol.)
Azobenzene film
POLARIZATION HOLOGRAPHY: RECONSTRUCTION
FFReference beam(Left-circular pol ) 0 order beam(Left-circular pol.) 0 order beam
(Left-circular pol.)Polarizationhologram
+1 order diffracted beam(Right-circular pol.)
hologram
(Right circular pol.)
POLARIZATION HOLOGRAPHY: RECONSTRUCTION
FF-1 order diffracted beam(Left circular pol )
Reference beam(Right-circular pol.)
(Left-circular pol.)
FPolarizationhologram F
0 order beam(Right-circular pol )(Right circular pol.)
JONES CALCULUSJONES CALCULUS
PRINCIPLE OF RECONSTRUCTIONPRINCIPLE OF RECONSTRUCTION
PRINCIPLE OF RETARDAGRAPHYPRINCIPLE OF RETARDAGRAPHY
yx
yx
zz
45 degree linear polarization45 degree-linear polarization
x-componenty-component
RecordingRecordinglaser
PRINCIPLE OF RETARDAGRAPHYPRINCIPLE OF RETARDAGRAPHY
yy
z
x
z
x
z
Phase difference
z
Phase difference(Polarization retardance)Elliptical polarization
x-componenty-componenty p
Recordinglaser
EXPERIMENTAL SETUPEXPERIMENTAL SETUP
OPTICAL RECORDINGBY RATARDAGRAPHY
SUMMARY IN RETARDAGRAPYSUMMARY IN RETARDAGRAPY
E l i f l i i h l hi h i i iExplanation of polarization holographic characteristics in photoinduced birefringent films
Complex amplitude of signal beam from an objectAmplitude: Retardance of photoinduced birefringencePhase: Principal axis of photoinduced birefringence
Complex amplitude of signal beam from an object
Application to phase-type optical recording by retardagraphy
Features of retardagraphyFeatures of retardagraphyRecording absolute retardance values using a single laser beamHigh robustness
MULTILAYER STRUCTURE BY SIPN COARTING
R. Katouf, T. Yatagai and S. Umegaki: Photonics & Nanostructure, 3, 116(2005).
MULTILAYER STRUCTURE BY SIPN COARTING
R. Katouf, T. Yatagai and S. Umegaki: Photonics & Nanostructure, 3, 116(2005).
SUMMARY & PROPOSALSSUMMARY & PROPOSALSFunctional photo material:
A b lAzobenzene 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)