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Fe:LiNbO3 crystal is one of the most
popular photorefractive materials due to it’s high
photorefractive sensitivity, excellent electro-optical and
chemo-mechanical properties, availability in large sizes at
moderate cost. This opens the way for wide application of
Fe:LiNbO3 both in R&D and practical devices for holographic
storage, optical memories and information processing.
Almaz Optics offers Fe:LiNbO3 elements fabricated to
customer’s specifications of fully poled, high optical quality
crystals grown by Czochralsky method. Wide range of available
dopant levels enables to adjust material properties to specific
customer application.
Material Properties
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Chemical Formula
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LiNbO3
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Doping Ions
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Fe2+, Fe3+
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Doping levels
( mol.% Fe2O3 in the melt )
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0.005; 0.02; 0.05; 0.1 (other on request)
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Crystal
symmetry
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Trigonal, 3m
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Density, g/cm3
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4.64
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Mohs hardness
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5
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Melting point , °C
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1255 (Tc=1140 )
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Transparency range, nm
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0.35 – 5.5
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Refractive Index at lambda=0.63 nm
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2.29 (no)
2.20 (ne)
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Electrooptic Coefficient ,pm/V (at lambda=0.63 nm)
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32 (r33) 6.8 (r22)
10 (r31)
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Dielectric Constant
( low frequency)
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85 (e11)
30 (e33)
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NOTE
1.
Crystals
are grown from congruent melt.
2.
Finished
elements are available in sizes (3–20)x(3–20)x(3–20)
mm3.Wafers with diameter up to 40 mm, or 30x30 mm square, 0.5 -
5.0 mm thick are available.
3.
Polish
standard: 20/10 S/D, lambda/4 flatness, parallelism < 2’
4.
Coatings
available:
a) AR @ 514 nm, 532 nm or other on request
b) ITO conductive/transparent coatings
5.
Optical
absorption in Fe:LiNbO3 strongly depends on doping level and
wavelength. For standard concentration of 0.05% it is near 1
cm-1 at 532 nm but it can be additionally adjusted in some
limits by annealing process in proper atmosphere due to change
relative concentrations of Fe2+ and Fe3+
ions in the LiNbO3 matrix.
6.
Standard
orientations: Z-cut, 45 deg. cut and 90 deg. cut.
Other orientations are available on request.
7.
Other
available photorefractive crystals: BGO, BSO, BTO, Fe:Ti:LiNbO3,
Fe:Ti:Ce:LiNbO3, crystals for UV photorefraction
(LiTaO3, LiIO3, undoped LiNbO3).
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