Beta Barium Borate



Beta Barium Borate (BBO or ß-BaB2O4) is an excellent optical non-linear crystal. It exhibits broad phase matching range, high non-linearity (about 6 times more than that of KDP), high optical damage threshold, good mechanical and temperature stability. This trigonal uniaxial crystal possesses wide transparency range from 190nm up to 2500nm.


Such non-linear crystal is used for harmonic generation (SHG, THG, 4HG, 5HG) of Nd:YAG laser, SHG, THG of Ti:Sapphire and Alexandrite laser, for tunable Optical Parametrical Oscillator (OPO) pumped by 355nm, 532nm or 1064nm laser radiation, for UV sources generated by SHG, SFG (Sum Frequency Generation) of dye laser and for autocorrelation (an optical pulse duration measurement technique) of ultra-short (ps and fs) laser. Further on BBO is used as Electro Optical (EO) Q-switch for example at 266nm. In such application it can be delivered in length up to 20mm and can be equipped with Cr/Au (Gold) coated electrodes attached to it.


Automatic technology (TSSG-method) allows to grow high quality crystals with 45mm-50mm diameter and 20mm length. Optical element sizes - (3mm–12mm) x (3mm–12mm) x (5mm–20mm), also 0.1mm-1.0mm thin plates are available.


Optical and spectral properties
Transmission range
189 ‐ 3500
Refractive index @532 nm
ne = 1,4525

no = 1,6749

Refractive index @ 1064 nm
ne = 1,5425

no = 1,6551

NLO coefficients in pm/V, @1064 nm
d22 = 2,2

d15 = d31 = 0,08

Absorption loss in %/cm @1064 nm
Temperature acceptance in °C·cm
24 (Typ I, 1064 nm SHG)
Angular acceptance in mrad·cm
1,2 (Typ I, 1064 nm SHG)
55,9 mrad (Typ I, 1064 nm SHG)
Physical properties
Chemical formula
Density in g/cm3
Melting point in °C
Lattice constants in Å
a= 12,532

b = 12,532

c = 12,717

Crystal structure
Thermal conductivity in W/(m·K)
1,2 (⊥ c-Achse)

1,6 (∥ c-Achse)

Thermal expansion in 1/K
α11 = 4 ·10-6

α33 = 36·10-6

Mohs hardness
Specific heat capacity in J/(kg · °C)
Spectral properties
sample thickness: 10 mm