α-BBO

High Temperature form BBO (α-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 α-BBO crystal are similar to those of b-BBO. However, the nonlinear properties of α-BBO crystal is vanished due to the centric symmetry with its crystal structure. It is not recommended to use for NLO processes.

α-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 α-BBO crystals to replace Calcite in many applications, especially in UV and high power operations.

Basic Properties of α–BBO
Please view Optical Crystals Properties

Sellmeier equations: (l in mm) :
n_o²=2.7359+0.01878/(l²-0.01822)-0.01354l²
n_e²=2.3753+0.01224/(l²-0.01667)-0.01516l²

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°

Specifications of α-BBO

Surface Quality	20/10 Scratch and Dig
Beam Deviation	<3 arc min.
Optical Axis Orientation	+/-0.5°
Flatness	l /4 @ 632.8 nm
Transmission Wavefront Distortion	< l /2 @632.8 nm
AR-coating	R<0.5%