Description:
a-BBO Crystal alpha -Barium Borate
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 crystal. However, there is no second order nonlinear effect in alpha-BBO 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.
Main applications:
- High power Beam displacersfor isolators.
- High power Polarizer
- Time delay compensators
Advantages:
- High UV transmittance
- Large birefringence
- High damage threshold
Basice properties of YVO4 crystal:
| 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） | no2=2.7471+0.01878/(λ2-0.01822)-0.01354λ2 ne2=2.37153+0.01224/(λ2-0.01667)-0.01516λ2 |
HGO offers a-BBO specifications:
| 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 |
