High Temperature form BBO ( a -BaB 2 O 4 ) is a negative uniaxial crystal. It has large birefringence over the broad transparent range from 189 nm to 3500 nm. 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, TiO 2 , and LiNbO 3 , 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.Claser 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 

Sellmeier equations: (l in mm) :
Refractive Indices, Birefringence ( D n = n e - n o ) and Walk-off Angle at 45 o ( r ):
at 1.0642 m m n e = 1.5379, n o = 1.6579 Dn =-0.073282 r = -4.9532°
at 0.5321 m m n e = 1.5534, n o = 1.6776 Dn =-0.075491 r = -5.0407°
at 0.2660 m m n e = 1.6114, n o = 1.7617 Dn=-0. 089805 r = -5.6926°
 Applications of a -BBO
Please refer to Polarizer for the applications of a-BBO

Specifications of a -BBO

Surface Quality
20/10 Scratch and Dig
Beam Deviation
<3 arc min.
Optical Axis Orientation
<L /4 @ 632.8 nm
Transmission Wavefront Distortion
< L /2 @632.8 nm