BBO

BBO


BBO (Beta-Barium Borate, β-BaB2O4 ), crystal is an important nonlinear optical crystals with combination of unique optical properties.Broad transmission and phase matching ranges, large nonlinear coefficient,high damage threshold and excellent optical homogeneity provide attractive possibilities for various nonlinear optical applicatios.

Advantage

Broad phase matching (SHG) range from 409.6nm to 3500nm
Wide transmission region from 190nm to 3500nm
Large effective SHG coefficient
High damage threshold of 10 GW/cm2 for 100 ps pulse-widths at 1064nm
High optical homogeneity with Dn 10-6/cm2 
Wide temperature bandwidth of about 55° (for type I SHG 1064nm)
Good mechanical and physical properties

 

Basic Properties

Crystal Structure Trigonal, Space group R3c
Lattice Parameter a=b=12.532Å,  c=12.717Å, Z=6
Melting Point     About 1095°C
Mohs Hardness     4
Density  3.85 g/cm3
Thermal Conductivity    1.2W/m/K(^c); 1.6W/m/K(//c)
Thermal Expansion Coefficient a,4x10-6/K; c,36x10-6/K
Transparency Range 190-3500nm
SHG Phase Matchable Range 409.6 ~ 3500nm  (Type I)
525-3500nm (Type II)
Therm-optic Coefficient dno/dT=-9.3X10-6
(°C, l in μm) dne/dT=-16.6X10-6
Absorption  Coefficient <0.1%/cm at 1064nm
<1%/cm at 532nm
Angle Acceptance 0.8mrad-cm    (q, Type I,1064 SHG)
1.27mrad-cm   (q, Type II,1064 SHG)
Temperature Acceptance 55°C-cm 
Spectral Acceptance 1.1nm-cm
Walk-off Angle  2.7° (Type I  1064 SHG)
3.2° (Type II  1064 SHG)
NLO Coefficien deff(I)=d31sinq+(d11cos3f- d22 sin3f) cosq                   
deff (II)= (d11 sin3f + d22 cos3f) cos2q
Non-vanished NLO susceptibilities d11 = 5.8 x d36(KDP)
d31 = 0.05 x d11
d22 < 0.05 x d11
Sellmeier  Equations no2=2.7359+0.01878/(λ2-0.01822)-0.01354λ2
(l in μm)       ne2=2.3753+0.01224/(λ2-0.01667)-0.01516λ2
Electro-optic coefficients γ11 = 2.7 pm/V, γ22, γ31 < 0.1γ11
Half-wave voltage 7 KV (at 1064 nm,3*3*20mm3)
Resistivity >1011 ohm-cm
Relative Dielectric Constant εs11 / εo : 6.7
εs33 / εo : 8.1
Tanδ<0.001

Coating Service

 - Dual Band AR-coating (DBAR) of BBO for SHG of 1064nm.
- Low reflectance (R<0.2% at 1064nm and R<0.5% at 532nm );
- High damage threshold (>300MW/cm2 at both wavelengths);
- Long durability.
- Broad Band AR-coating (BBAR) of BBO for SHG of tunable lasers.
- Broad Band P-coating of BBO for OPO applications.
- Other coatings are available upon request.

 Capability

Common Specification
Dimension Tolerance (W±0.1mm)x(H±0.1mm)x(L+0.5/-0.1mm) (L≥2.5mm)
(W±0.1mm)x(H±0.1mm)x(L+0.2/-0.1mm) (L<2.5mm)
Clear aperture Central 90% of the diameter
Flatness ≤ Lambda/8 @ 632.8nm
wavefront distortion ≤ Lambda/8 @ 632.8nm
Bevel ≤0.2mm@45°
Chip ≤0.1mm
Surface Quality S/D 10-5
Parallelism ≤ 20 arc seconds
Perpendicularity ≤ 5 arc minutes
Angle tolerance ≤0.1°
Damage threshold[GW/cm ]:  >1 for 1064nm, TEM00, 10ns, 10HZ (polished only) 
>0.5 for 1064nm, TEM00, 10ns, 10HZ (AR-coated)
>0.3 for 532nm,  TEM00, 10ns, 10HZ (AR-coated)

Notes

- BBO has a low susceptibility to the moisture. The user is advised to provide dry conditions for both the use and preservation of BBO.
- BBO is relatively soft and therefore requires precautions to protect its polished surfaces.
- When angle adjusting is necessary, keep in mind that the acceptance angle of BBO is small.