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Home >> Birefringent Crystals >> a-BBO 

High temperature phase of BaB 2 O 4 is an excellent birefringent crystal; it is characterized by large birefringent coefficient and wide transmission window from 189nm to 3500nm, particularly it is suitable to make the high power UV polarizer, due to its unique UV transparency and good mechanical properties.


The physical, chemical, thermal and optical properties of a -BBO crystals are similar to those of b -BBO, for instant high optical homogeneity(better than 1x10-6/cm), extremely low absorption in the UV to IR range (<0.5% from 300-2300nm), low hygroscopic susceptibility, high damage threshold. However, the nonlinear optical properties of a -BBO is vanished due to the centric symmetry with its crystal structure.

Physical and Optical Properties
Transparency Range 190-3500nm
Density 3.85g/cm3
Therm-Optic Coefficients dn o / dT = -9.3 X 10 -6 / °C
dn e / dT = -16.6.3 X 10 -6 / °C
Optical Homogeneity ?n ˜ 10-6/cm
Damage Threshold 1 GW/cm2 at 1064nm500 MW/com2 at 532nm
Hygroscopic Susceptibility Low
Thermal Expansion Coefficients
a a = 4 X 10 -6 / K
a c = 436X 10 -6 / K
Linear Absorption Coefficients a<0.005cm -1 from 300nm to 2300nm
Refractive Indices, Birefringence
(?n=ne-no) and Walk-Off Angle at 45°C(?)
ne=1.58462, no=1.65790, ?n=-0.073282; ?=-4.9532o at 1064nm
ne=1.60206, no=1.67755, ?n=-0.075491; ?=-5.0407o at 532nm
ne=1.67190, no=1.76171, ?n=-0.089805; ?=-5.6926o at 266nm

1) Diameter : max 40~50mm
2) Length: max 25~35mm
3) Surface Quality: better than 20/10 scratch/dig Per MIL-0-13830A
4) Beam Deviation: <3 arc min
5) Optical Axis Orientation: +/-0.5°
6) Flatness: 7) Transimission Wavfront Distortion: < l /2 @633nm
8) Coating: upon customer's specification

Note:Please click here for more detail about a-BBO Polarizers.