Almaz Optics, Inc.
12 Chadsford Ct.  Marlton, NJ 08053, USA
Tel:  856 797-0491, Fax: 856 797-0228



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

Chemical Formula


Doping Ions

Fe2+, Fe3+

Doping levels
( mol.% Fe2O3 in the melt )

0.005; 0.02; 0.05; 0.1 (other on request)

Crystal symmetry

Trigonal, 3m

Density, g/cm3


Mohs hardness


Melting point , °C

1255 (Tc=1140 )

Transparency range, nm

0.35 – 5.5

Refractive Index at lambda=0.63 nm

2.29 (no)
2.20 (ne)

Electrooptic Coefficient ,pm/V (at lambda=0.63 nm)

32 (r33) 6.8 (r22)
10 (r31)

Dielectric Constant
( low frequency)

85 (e11)
30 (e33)


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).