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BBO Nonlinear Crystal Laser Crylink

BBO Crystal - Beta barium borate crystal

β-BBO Crystal—a widely used nonlinear crystal for frequency conversion in the ultraviolet, visible and near-infrared

BBO Crystal is one of the essential nonlinear optical crystals. Beta-barium borate (β-BaB2O4,β-BBO) combines many outstanding features such as its high nonlinear optical coefficients and low group-velocity dispersion, broad transparency range (189–3500 nm) high damage threshold. This unique combination ensures that β-BBO crystal is a promising candidate for nonlinear optical applications such as frequency converters and optical parametric oscillators. In quantum optics, β-BBO crystal can generate entangled photon pairs and ten-photon entanglement.

BBO nonlinear crystal is a negative uniaxial crystal. It provides phase matching for various second-order interactions almost over its entire transparency range. This transparency ranges from 185 nm to 3.3 µm, as inferred from transmittance measurements using crystal samples of a few mm thickness. It is widely used for nonlinear frequency conversion in the ultraviolet, visible, and near-infrared. The BBO crystal is the most critical nonlinear crystal for near-infrared optical parametric chirped-pulse amplifiers, which currently deliver few optical cycle pulses with high average and ultrahigh peak powers.


Chemical FormulaBaB2O4
Crystal Structuretrigonal, 3m
Lattice Parametera=b=12.532Å,c=12.717Å, Z=6
Mass Density3.85 g/cm3
Moh Hardness4
Melting PointAbout 1095°C
Thermal Conductivity1.2 W/m/K (⊥c); 1.6 W/m/K (//c)
Thermal Expansion Coefficientα,4×10-6/K; c,36×10-6/K
Birefringencenegative uniaxial
Transparency Range189 – 3500 nm
Absorption Coefficientα<0.1%/cm @1064nm
Refractive Indices
at 1.0642 μmne = 1.5425, no = 1.6551
at 0.5321 μmne = 1.5555, no = 1.6749
at 0.2660 μmne = 1.6146, no = 1.7571
Sellmeier Equations(λ in μm)no2(λ) = 2.7359+0.01878/(λ2-0.01822)-0.01354λ2
ne2(λ) = 2.3753+0.01224/(λ2-0.01667)-0.01516λ2
SHG Phase Matchable Range409.6 ∼ 3500nm (Type I); 525 ∼ 3500nm (TypeII)
NLO Coefficientsd11= 5.8 x d36(KDP); d31 = 0.05 x d11; d22< 0.05 x d11
deff(I)=d31sinθ+ (d11cos3φ – d22sin3φ)cosθ
deff(II)=(d11sin3φ+ d22cos3θ)cos2θ
Therm-Optic Coefficientsdno/dT = – 9.3 x 10-6/C
dne/dT = -16.6 x 10-6/C
Electro-Optic Coefficientsg11= 2.7 pm/V, g22, g31< 0.1 g11
Half-Wave Voltage48 KV (at 1064 nm)
Damage Threshold
 at 1.064 μm5 GW/cm2 (10 ns); 10 GW/cm2 (1.3 ns)
 at 0.532 μm1 GW/cm2 (10 ns); 7 GW/cm2 (250 ps)
nonlinear crystal BBO transmission spectrumthe SHG tuning curve of BBO
BBO Transmission SpectrumThe SHG Tuning Curve of BBO
BBO’s OPO tuning curves type I OOE under different pump lamps, 53nm,355nm and 266nmBBO’s OPO tuning curve type II EOE under different pump lamps 530 nm 355 nm and 266 nm

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