High power Beam displacers for isolators.
High power Polarizer
Time delay compensators
High UV transmittance
Large birefringence
High damage threshold
Low hygroscopic susceptibiliy
High temperature phase BBO ( alpha-BBO, a-BBO) is a negative uniaxial crystal with a large birefringence over the broad transparent range from 189 nm to 3500 nm. The physical, chemical, thermal and optical properties of alpha-BBO crystal are similar to those of low temperature phase beta-BBO. There is no second order nonlinear effect in alpha-BBO crystal due to the centric symmetry in its crystal structure and thus it has no use for NLO processes. Instead, alpha-BBO is widely used for fabrication of polarizers, polarizing beam displacers, phase retarders, birefringent plates, and time delay compensators especially those involving UV and high power lasers.
Basic Properties
| Crystal Structure | Trigonal |
| Transparency Range | 190-3500 nm |
| Density | 3.85 g/cm3 |
| Hygroscopic Susceptibility | Low |
| Hardness | 4.5 Mohs |
| Thermal Expansion Coefficient | -9.3 × 10-6 /℃（C） -9.5 × 10-6 /℃（A） |
| Damage Threshold | ＞1 GW/cm2@1064 nm 10 ns, 10 Hz (AR-coated) |
| Refractive Indices | no=1.6776,ne=1.5534@532nm |
| no=1.6579,ne=1.5379@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 |
| Size | Up to Φ50mmx40mm |
| Surface Quality | 10/5 to MIL-PRF-13830B |
| Flatness | λ/4 @633 nm |
| Optical Axis Orientation | 6 arc min |
| Parallelism | 20 arc sec |
| Clear Aperture | ＞ 90% |
| Coating | AR-coating or P-coating |
| Mount | Upon Customer's Specification |
