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Alpha-BBO Crystals

Alpha-BBO Crystals

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Features
 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, CryLight 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.
Specifications
Specifications:
Diameter: Max 50m
Length: Max 35mm
Surface Quality: better than 20/10 scratch/dig
Beam Deviation: < 3 arc min
Optical Axis Orientation: +/-0.2deg
Flatness: < λ/4 @632.8nm
Wavefront Distortion: < λ/2 @632.8nm
Coating: Coating upon Request

Properties:
Transmitting range 189nm~3500nm
Density 3.85g/cm3
Therm-Optic Coefficients dno/dT=-9.3 x 10-6/ °C
dno/dT=-16.6x10-6/ °C
Optical Homogeneity △n»10-6/cm
Mohs Hardness 4.5
Damage Threshold 1GW/cm2 at 1064nm
500MW/cm2 at 532nm
Hygroscopic Susceptibility Low
Thermal Expansion Coefficients aa=4x10-6
(25 °C - 900 °C) aa=4x10-6
Linear Absorption Coefficients a<0.005cm-1 from 300nm to 2300nm
Refractive Indices,
Birefringence(Dn=ne-no)
and wal-off Angle at 45 °C(r)
ne=1.58462,no=1.65790,△n=-0.073282;r=-4.9532° at 1064nm
ne=1.60206,no=1.67755,△n=-0.075491;r=-5.0407° at 532nm
ne=1.67190,no=1.76171,△n=-0.089805;r=-5.6926° at 266nm
Sellmeier equation(l in mm) no2=2.7471+0.01878/(λ2-0.01822)-0.01354λ2
ne2=2.3174+0.01224/(λ2-0.01667)-0.01516λ2