BBO (偏硼酸钡)

BBO (偏硼酸钡)


BBO晶体是一种新型的紫外倍频晶体,具有较大的相位匹配范围以及较宽的透过波段,其倍频转换效率比较高,并具有很高的激光损伤阈值。

优点

可实现相位匹配的波段范围宽(409.6~3500nm)
可透过波段范围宽(190~3500nm)
倍频转换效率高(相当于KDP晶体的6倍)
光学均匀性好
高损伤阈值(100ps脉宽的1064nm10GW/cm2)
温度接收角宽(55℃左右)

 

基本特性

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

镀膜

 - 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.

 加工能力

常规精度等级
尺寸公差 (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)
通光孔径 Central 90% of the diameter
面形 ≤ Lambda/8 @ 632.8nm
波前畸变 ≤ Lambda/8 @ 632.8nm
倒边 ≤0.2mm@45°
崩边 ≤0.1mm
表面光洁度 S/D 10-5
平行度 ≤ 20 arc seconds
垂直度 ≤ 5 arc minutes
角度公差 ≤0.1°
损伤阈值[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.