Sillenite Photorefractive Crystals

Sillenite type monocrystals Bi12SiO20 (BSO) and Bi12GeO20 (BGO) display unique combination of different physical properties. Crystals BSO and BGO are very efficient photoconductors with low dark conductivity. Strong spectral dependence of the photoconductivity allows to produce a wide range of optical device and systems. Combination of electro-optical and photoconductive properties display photorefractive effect (PR) in the crystals. Sillenite crystals (BSO, BGO) are used like photoconductor in optically-addressed spatial light modulators (OASLM), optically-addressed light valve (OALV) and liquid crystal light valves (LCLV) with electro-optical modulation into liquid crystal medium. Both crystals BSO, BGO are used like electro-optic and photoconductive mediums for construction of PROM, PRIZ spatial modulators. Sillenite crystals are applied in dynamic real-time hologram recording devices, optical correlators, and optical laser systems for adaptive correction of ultra short light pulses. Production of sillenite thin-film crystal structures by different technologies permits the development of a long list of devices including optical waveguides, integrated optical devices. Crystals BSO, BGO are used in optical fiber electric and magnetic fields sensors. BGO crystals are used successfully in optical current sensors (OCS).

Crystal Bi12SiO20 (BSO) Bi12GeO20 (BGO)
Crystal Structure cubic cubic
Lattice Parameters, A 10.10 10.15
Transmission Range, mkm 0.4 – 6 0.4 – 7
Refractive Index at 633nm 2.54 2.55
Electro-Optic Coefficient r41, pm/V 5.0 3.5
Optical Activity, deg/mm at 633 nm 20.5 20.4
Density, g/cm3 9.15 9.2
Mohs Hardness 5 5
Melting Point, C 890 920
Dielectric Constant 56 40