Beta Barium Borate (BBO) Non-linear crystals
Beta Barium Borate (BBO), is widely used non-linear optical material with an excellent range of properties making useful across a broad range of applications.

BBO strengths include:
  • Wide transmission/transparency range
  • Broad phase-matching range
  • Large non-linear coefficient
  • High damage threshold
  • Wide thermal acceptance bandwidth
  • Low wavefront distortion

BBO applications include:
  • Harmonic generation using Nd:YAG and Nd:YLF lasers
  • NOPA with fast fsec pulses
  • OPO using Nd:YAG pump
BBO Crystal - Availability
Format: Rods, Discs and Slabs
Sizes: Diameter: 25mm max and Length: 40mm max
BBO Crystal Properties
Linear Optical Properties Units Value
Transmission/Transparency Range µm 0.189 - 3.50
Optical Homogeneity cm‾¹ δn ~ 10‾⁶
Refractive Index (n) @213nm n₀ = 1.8465
ne = 1.6742
@266nm n₀ = 1.7571
ne = 1.6139
@355nm n₀ = 1.7055
ne = 1.5775
@532nm n₀ = 1.6750
ne = 1.5555
@1064nm n₀ = 1.6551
ne = 1.5426
Absorption Coefficient @1.06µm cm‾¹ <0.1
@2.5µm cm‾¹ TBA
@5.0µm cm‾¹ N/A
@7.5µm cm‾¹ N/A
@10.0µm cm‾¹ N/A
@11.0µm cm‾¹ N/A
Thermo-optic Coefficients 10‾⁶/ºC dn₀/dt = -9.3 dne/dt = -16
Physical / Thermal Properties Units Value
Chemical Formula BaB₂O₄
Crystal Symmetry Trigonal
Space Group R3c
Point Group 3m
Cell Parameters a = b=12.532Å
c=12.717Å
z=6
Melting Point ºC 1095
Thermal Expansion Coeff. @20ºC 10‾⁶/ºC a: 4
b: 36
Thermal Conductivity Coeff. @20ºC W/m/ºK ┴ 1.2
║ 1.6
Specific Heat cal/g K 0.497
Density g/cm³ 3.85
Mohs Hardness 4.5
Optical Damage Threshold @1.064,10ns MW/cm² 5000
Nonlinear Optical Properties
NLO Coefficients d₁₁ = 5.8 x d₃₆ KDP
d₃₁ = 0.05 x d₁₁
d₂₂ < 0.05 x d₁₁
Effective Nonlinearity Expressions TBA
Electro-optic Coefficients y₁₁ = 2.7 pm/V
y₂₂ < 0.1 x y₁₁
y₃₁ < 0.1 x y₁₁
Half-wave Voltage 48 kV @ 1064nm
@10.0µm
Standard Applications/Cuts Type θº φº
SHG@800nm/400nm I 29.2 90
THG@800nm/266nm I 44.3 90
SHG@1030nm/515nm I 23.4 90
4HG@1064nm/266nm I 47.6 90
BBO Crystal - Sellmeier Equations
n₀²(λ) = 2.7359 + 0.01878 / (λ² - 0.01822) - 0.01354lλ²

ne²(λ) = 2.3753 + 0.01224 / (λ² - 0.01667) - 0.01516λ²