OST Photonics α-BBO Crystals

α-BBO (α-BaB2O4) is a negative uniaxial crystal which has large birefringence over a broad transparent range of 190nm to 3500nm. α-BBO is an excellent crystal especially in UV and high power applications.

The physical, chemical, thermal, and optical properties of alpha-BBO crystal are similar to those of Beta-BBO. However, there is no second order nonlinear effect in alpha-bbo nonlinear crystal due to the centrosymmetry in its crystal structure and thus it has no use for second order nonlinear optical processes. Instead, alpha-BBO is widely used for fabrication of polarizers, polarizing beam displacers, phase retarders, birefringent plates, and time delay compensators especially those for UV and high power lasers.

Applications of α-BBO Crystals


High power Beam displacers for isolators.

High power Polarizer

Time delay compensators
 
Advantages of α-BBO Crystals

High UV transmittance

Large birefringence

High damage threshold

Specifications of α-BBO Crystals

Tolerance of cutting angle △θ≤¯0.25®,△φ≤¯0.25®
Dimension Tolerance ¯0.1mm
Flatness λ/10 @ 632.8nm
Wavefront distortion λ/4@ 632.8nm
Surface Quality 10/5 per MIL-O-13830B
Parallelism 10″
Perpendicularity 10′
Bevel/Chamfer <0.1mm@45deg.
Chips <0.1mm
Clear Aperture >95%
Coating AR/HR (IAD, EB, IBS) coating upon customer’s request
Damage Threshold 750MW/CM2 at 1064nm, TEM00, 10ns, 10Hz
Quality Warranty Period One year under proper use
 
Basic Properties of α-BBO Crystals

Transparency Range 190-3500nm
Hygroscopic Susceptibility Low
Density 3.85g/cm3
Mohs Hardness 4.5
Thermal Expansion Coefficients（/℃） 9.3×10^-6（C）
9.5×10^-6（A）
Damage Threshold 1GW
Refractive Indices no=1.6776，ne=1.5534，at 532nm
no=1.6579，ne=1.5379，at 1064nm
Sellmeier Equation（λ in μm） no°=2.7471+0.01878/(λ°-0.01822)-0.01354λ°
ne°=2.37153+0.01224/(λ°-0.01667)-0.01516λ°

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