Lithium Triborate (LiB3O5 or LBO) is an excellent nonlinear optical crystal.

Features of LBO Crystals:

  • Broad transparency range from 160nm to 2600nm ;

  • High optical homogeneity (δn≈10-6/cm) and being free of inclusion;

  • Relatively large effective SHG coefficient (about three times that of KDP);
  • High damage threshold;
  • Wide acceptance angle and small walk-off;
  • Type I and type II non-critical phase matching (NCPM) in a wide wavelength range;
  • Spectral NCPM near 1300nm.

Basic Properties:

Crystal Structure
Orthorhombic, Space group Pna21, Point group mm2
Lattice Parameter
Melting Point
About 834℃
Mohs Hardness
Thermal Expansion Coeficients
αx=10.8x10-5/K, αy=-8.8x10-5/K,αz=3.4x10-5/K
Thermal Conductivity Coefficients
Transparency Range
SHG Phase Matchable Range
551-2600nm  (Type I)      790-2150nm (Type II)
Therm-optic Coefficient (/℃, λ in μm)
Absorption  Coefficients
<0.1%/cm at 1064nm    <0.3%/cm at 532nm
Angle Acceptance
6.54mrad·cm    (φ, Type I,1064 SHG)
15.27mrad·cm    (θ, Type II,1064 SHG)
Temperature Acceptance
4.7℃·cm   (Type I, 1064 SHG)
7.5℃·cm   (Type II, 1064 SHG)
Spectral Acceptance
1.0nm·cm (Type I, 1064 SHG)
1.3nm·cm (Type II, 1064 SHG)
Walk-off Angle
0.60°  (Type I  1064 SHG)
0.12°  (Type II  1064 SHG)
Technical Parameters:

  • 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+0.1/-0.1mm)  (L<2.5mm)

  • Clear aperture: central 90% of the diameter
  • No visible scattering paths or centers when inspected by a 50mW green laser
  • Flatness: less than  λ/8 @ 633nm
  • Transmitting wavefront distortion: less than λ/8 @ 633nm
  • Chamfer: ≤0.2mm x 45°
  • Chip: ≤0.1mm
  • Scratch/Dig code: better than 10/ 5 to MIL-PRF-13830B
  • Parallelism: better than 20 arc seconds
  • Perpendicularity: ≤5 arc minutes
  • Angle tolerance: △θ≤0.25°, △φ≤0.25°
  • Damage threshold[GW/cm2 ]: >10 for 1064nm, TEM00, 10ns, 10HZ (polished only)
                                                      >1    for 1064nm, TEM00, 10ns, 10HZ (AR-coated)
                                                      >0.5 for 532nm,   TEM00, 10ns, 10HZ (AR-coated)