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


Bismuth Germanate, Bi4Ge3O12

Bismuth Germanate Crystals of Evlitine structure (Bi4Ge3O12) became well – known primarily due to it’s wide application as scintillation material for high energy physics. However this crystal processes also relatively high electro-optic coefficients which makes it useful for building Pockels cells, particularly, for application in optical fiber electric field sensors with high thermal stability. The crystal can be used also for photorefractive devices working in the UV range.

ELAN fabricates custom designed elements of Bi4Ge3O12 crystals grown by Czochralsky method and carefully selected and tested for high optical homogeneity, absence of bubbles, inclusions and other defects.

Material Properties

Crystal symmetry

Cubic, 43m

Lattice parameter, A


Density, g/cm3


Mohs hardness


Melting point , °C


Transparency range, ΅

0.3 - 5

Refractive Index


Optical Absorption, cm-1


Electro-Optical Coefficient (r41),pm/V


Dielectric Constant
( low frequency)



1.      If not specified, optical properties are given for wavelength 633 nm.

2.      Finished elements are available in sizes (3–30)x(3–30)x(3–120) mm3. Wafers with diameter up to 60 mm, or 40x40 mm square, 0.5 - 10.0 mm thick are available.

3.      Polish standard: 40/20 S/D, 1/2 wave flatness, parallelism < 3’

4.      Coatings available:
   a) AR @ 514.5 nm, 532 nm or other on request
   b) ITO conductive/transparent coatings
   c) electrodes Cr + Au