Crystals Land

  BSO  BGO

 Bi₁₂SiO₂₀ (BSO) & Bi₁₂GeO₂₀ (BGO) are the most popular photorefractive crystals. Their fortunate combination of photorefractive, electrooptic and other properties makes it promising materials for optoelectronics.

 Physical Properties:

	BSO	BGO
Crystal Symmetry	Cubic	Cubic
Density	9.20g/cm3	9.22g/cm3
Mohs Hardness	5	4.5
Melting Point	900°C	925°C
Transparancy Range,	0.45 - 6 mm	0.45 - 7 mm
Refractive Index at l=0.63 mm	2.54	2.55
Electrooptical Coefficient (pm/V at 0.63microns)	r41=5.0	r41=3.5
Dielectric Constant( low frequency)	56	40

 Specifications:

Wavefront distortion	less than l/8 @ 633nm
Dimension tolerance	(W ± 0.1mm) x (H ± 0.1mm) x (L + 0.2mm/-0.1mm)
Clear aperture	> 90% central area
Flatness	l/8 @ 633nm
Scratch/Dig	10/5 to MIL-O-13830A
Parallelism	better than 20 arc seconds
Perpendicularity	5 arc minutes
Angle tolerance	Dq < ± 0.3°,D f< ±0.3°