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| 所属类别： |
光学晶体 |
| 商品名称： |
a-BBO |
| 浏览次数： |
857 次 |
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Barium Borate (a-BBO) Crystal
High Temperature form BBO (a-BaB2O4) is a negative uniaxial crystal. It has large birefringence over the broad transparent range from 189 nm to 3500 nm. Recently, CASTON has succeeded in growing this crystal into large size. The physical, chemical, thermal and optical properties of a-BBO crystal are similar to those of b-BBO. However, the nonlinear optical properties of a-BBO crystal is vanished due to the centric symmetry with its crystal structure. It is not recommended to use for NLO processes.
a-BBO is an excellent crystal to replace Calcite, TiO2, and LiNbO3, etc. in Glan-Taylor and Glan-Thompson polarizers as well as walk-off beam splitters, especially for high power and UV polarizer, due to its unique UV transparency, good mechanical properties and high damage threshold. CASTON manufactures and supplies Glan-Laser, Glan-Taylor, Glan-Thompson Polarizers and other beam displacers from high quality a-BBO crystals to replace Calcite in many applications, especially in UV and high power operations.
1. Basic Properties of a-BBO
Transparency Range:
189 - 3500 nm, See Transparency Curve |
Transparency Curve of a-BBO
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| Density: 3.85 g/cm3 |
Therm-Optic Coefficients:
dno/dT = -9.3 x 10-6/oC
dne/dT = -16.6 x 10-6/oC |
Damage Threshold
at 1064 nm 1GW/cm2
at 355 nm 500 MW/cm2 |
| Optical Homogeneity:Dn » 10-6/cm |
| Mohs Hardness: 4.5 |
| Hygroscopic Susceptibility:Low |
Thermal Expansion Coefficients
(in the range of 25oC – 900oC) |
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° |
2. Specifications of a-BBO
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Surface Quality
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20/10 Scratch and Dig
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Beam Deviation
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<3 arc min.
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Optical Axis Orientation
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+/-0.5°
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Flatness
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l/4 @ 632.8 nm
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Transmission Wavefront Distortion
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<l /2 @632.8 nm
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AR-coating
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R<0.5%
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