High temperature phase of BaB2O4 is an excellent birefringent crystal, it is characterized by large birefringent coefficient and wide transmission window from 189nm to 3.5mm, particularly it’s suitable to make UV polarizer for high power application.
The physical, chemical, thermal and optical properties of a-BBO crystals are similar to those of b-BBO, for instant high optical homogeneity, extremely low absorption in UV to IR range, low hygroscopic susceptibility, high damage threshold.
a-BBO physical properties are similar to BBO.
Basic Properties of a-BBO
Transparency Range:
189 - 3500 nm, See Transparency Curve
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Transparency Curve of a-BBO
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Density: 3.85 g/cm3
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Therm-Optic Coefficients:
dno/dT = -9.3 x 10-6/oC
dne/dT = -16.6 x 10-6/oC
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Damage Threshold
at 1064 nm 1GW/cm2
at 355 nm 500 MW/cm2
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Optical Homogeneity:Dn » 10-6/cm
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Mohs Hardness: 4.5
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Hygroscopic Susceptibility:Low
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Thermal Expansion Coefficients
(in the range of 25oC – 900oC)
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aa= 4 x 10-6/K
ac= 36 x 10-6/K
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Linear Absorption Coefficients: a <0.005 cm-1 from 300 nm to 2300 nm
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Refractive Indices, Birefringence (Dn = ne - no) and Walk-off Angle at 45o (r):
at 1.0642 mm ne= 1.5379, no = 1.6579 Dn =-0.073282 r =-4.9532°
at 0.5321 mm ne = 1.5534, no = 1.6776 Dn =-0.075491 r =-5.0407°
at 0.2660 mm ne = 1.6114, no = 1.7617 Dn=-0.089805 r =-5.6926°
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Specifications:
Dimension tolerance
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±0.1mm
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Angle tolerance
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<0.5°
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Surface flatness
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l/8@632.8nm
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Wavefront distortion
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l/8@632.8nm
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Surface quality
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20-10
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Parallelism
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<20 arcsec
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Perpendicularity
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<5 arcmin
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Clear aperture
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>80%
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