metrolux Optische Messtechnik GmbH

Photorefractive Crystals

Fe: LiNbO3

BaTiO3

Ce:BaTiO3

Fe: LiNbO₃

Fe: LiNbO₃ is a kind of common used photorefractive materials with large electro-optic (E-O) coefficients, high photorefractive sensitivity and high diffraction efficiency.

It is easy operation and storage, low cost and large size availability, which make it more suitable for volume fabrication and practical devices.

We provide high quality Fe:LiNbO₃ crystals, which are all poled and strain and scatter free. The iron level we can provide is from 0.005 to 0.20mol% with size 40x40x40mm or 3" in diameter.

Crystal Structure	Trigonal, space group R3c
Cell Parameters	5148, c=13.863, z=6
Melting Point	1255°C
Curie Point	1140°C
Mohs Hardness	5
Density	4.64g/cm3
Color	Colorless to brown
Solubility	Insoluble in H ₂ O

BaTiO3

BaTiO3 is an excellent photorefractive crystal for self-pumped phase conjugation, four-wave mixing and many other photorefractive processes. It has high beamcoupling gain and short beam-coupling rise time. The highest SPPC reflectivity was reported by using BaTiO3 , It can be operated at visible and near-infraced regions and is good for cw four-wave mixing with milliwatts optical power.

Crystal structure Tetragonal, 4mm

Lattice parameters a=3.992° , c=4.036°

Density 6.02g/cm³

Hardness Mohs Moths 5

Phase transition temperature -90°, 9°, 132°

Electro-optic coefficients Unclamped Clamped

r 13 19.5 pm/v 8 pm/v

r ₃₃ 97 pm/v 28 pm/v

r 42 1460 pm/v 820pm/v

Dielectric Constants ea=3600 ea=2400

e c=2400 ec=60

Ce:BaTiO3

Ce:BaTiO3 is a new crystal with excellent photorefractive properties and optical quality .The formation _of self-pumped phase conjugate(SPPC) wave in this crystal is based on the backward stimulated photorefractive scattering in air without any external seed beam. Therefore, the reflectivity of SPPC is highly insensitive to the incident angle, the inclination and the pitch of crystal. It's easy to obtain SPPC wave. Notes:

1)
Maintain the storage temperature above 13°C(55°F) and below 120°C(248°F) to prevent the phase transition.

2)
One faces polished for self-pumped phase conjugating mirrors.

3)
Two faces polished for two wave mixing.

4)
Six faces polished for self-pumped phase conjugation.

Crystal Structure Tetragonal 4mm

Transparent Range 0.45-6.3um

Refractive Indices n _o =2.4921, n e =2.4247 @515nm
n _o =2.4160, n e =2.3630 @633nm
n _o =2.3681, n e =2.3235 @775nm

Electro-Optic Coefficients r 13 =11.7pm/v, r ₃₃ =112pm/v, r 42 =1920pm/v

Reflectivity of SPPC 50-70%, l =515nm
50-80%, l =633nm
>70%, l =670nm

Two wave mixing coupling constant 10-40cm ^-1

Absorption Loss(cm ^-1 ) 3.392@515nm
0.268@633nm
0.005@775nm

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