Beta-barium borate (BBO) has the following exceptional properties that make it a very important nonlinear crystal, BBO is grown with the flux method. It is a negative uniaxial crystal, with ordinary refractive-index (no) larger than extraordinary refractive-index (ne).

SHG phase-matching range from 410 nm to 2100 nm
Transmission from 190 nm to 3500 nm
Large effective nonlinear coefficient
High damage threshold ;
Wide temperature-bandwidth of about 55°C. 

Physical and Chemical Properties:
Please view NLO crysals physical Properities.

The Sellmeier equations (l in µm ):
no2=2.7359+0.01878/(l 2-0.01822)-0.01354l 
l 2-0.01667)-0.01516l 2 

Optical and Spectral Properties:
Please view NLO crysals optical and nonlinear optical Properities. 

BBO is of particular importance in the visible and far UV. A wide variety of phase-matching applications are possible, including the following:
Second, third, fourth and fifth harmonic generation of Nd doping lasers;
Frequency-doubling, -tripling and -mixing of Dye lasers;|
Second, third and fourth harmonic generation of Ti:Sapphire lasers;
Optical parametric amplifier (OPA) and optical parametric oscillators (OPO);

BBO's Specifications:

Dimension tolerance (W ± 0.1 mm) x (H ± 0.1 mm) x (L + /-0.2 mm)
Transmitting wavefront distortion: lambda/8 @ 633 nm
Clear aperture: > 90% central area
Flatness: lambda/8 @ 633 nm
Scratch/Dig code: 10/5 to MIL-O-13830A
Parallelism: better than 20 arc seconds
Perpendicularity: 15 arc minutes
Angle tolerance: Δθ < ±0.3°, Δφ < ± 0.3°
AR coating: R< 0.1% at 1064nm and R<0.4% at 532 nm.
Quality Warranty Period: one year under proper use.