BBO Crystal

Beta-Barium Borate (β-BBO) is an excellent nonlinear crystal with combination of a number of unique features: wide transparency region, broad phase-matching range, large nonlinear coefficient, high damage threshold, and excellent optical homogeneity. Therefore, β-BBO provides an attractive solution for various nonlinear optical applications such as OPA, OPCPA, OPO etc.

β-BBO also has advantages of large thermal acceptance bandwidth, high damage threshold and small absorption, thus is very suitable for frequency conversion of high peak or average power laser radiation, e.g. harmonic generation of Nd:YAG, Ti:Sapphire and Alexandrite laser radiation. β-BBO is the best NLO crystal for the fifth harmonic generation of Nd:YAG laser at 213 nm. Good laser beam quality (small divergence, good mode condition, etc.) is the key for BBO to obtain high conversion efficiency.

In addition, large spectral transmission range as well as phase matching, especially in UV range, makes β-BBO perfectly suitable for frequency doubling of the Dye, Argon ion and Copper vapour laser radiation. Both Type 1 (oo-e) and Type 2 (eo-e) phase-matching angles can be obtained, increasing the number of advantages for different applications of β-BBO.

Alpha-Barium Borate (α-BBO) is a negative uniaxial crystal with large birefringence and broad transparent range from UV (190 nm) to mid-infrared (3500 nm). α-BBO grown by WISOPTIC has very good internal quality, less absorption, high extinction ratio and high UV transmission. α-BBO is widely used in deep UV and high power laser systems as devices of Gran prisms, polarizing beam splitters, compensator and so on.

The physical, chemical, thermal and optical properties of α-BBO are similar to those of β-BBO. However, α-BBO has no nonlinear optical property due to its centric symmetry structure while β-BBO is recommended in the NLO systems for its acentric symmetry structure. 

WISOPTIC Standard Specifications* - BBO 

 Main Features of β-BBO

• Broad transparency range (189-3500 nm)
• Broad phase matching range (410-3500 nm)
• High optical homogeneity（δn≈10^-6/cm）
• Relatively large effective SHG coefficient (about 6 times that of KDP)
• High damage threshold (compared with KTP and KDP)

Comparison of bulk damage threshold [1064nm, 1.3ns]

Primary Applications of β-BBO

• 2~5 HG (Harmonic generation) of Nd-doped YAG and YLF laser.
• 2~4 HG of Ti:Sapphire and Alexandrite laser.
• Frequency doublers, triplers, and wave mixers of Dye laser.
• Frequency doublers of Argon ion, Ruby, and Copper vapour laser.
• Widely tunable OPO, OPA, OPCPA of both Type I and Type II phase matching.

Physical Properties of β-BBO

Optical Properties of β-BBO

WISOPTIC Advantages of α-BBO

• High UV transmittance
• Large birefringence
• High damage threshold
• Stable physical and mechanical properties