LBO Crystal (Lithium Triborate)

 Crystals >>> Nonlinear Crystals >>>  LBO Crystal (Lithium Triborate)

Lithium Triborate LiB3O5 or LBO is a newly developed nonlinear optical crystal. It is unique in many aspects, especially its wide transparency range, moderately high nonlinear coupling, high damage threshold and good chemical and mechanical properties. Its transmission range is from 0.21 m to 2.3 m. LBO allows temperature-controllable non-critical phase-matching (NCPM) for 1.0-1.3 m, Type I SHG, and also provides room temperature NCPM for Type II SHG at 0.8-1.1 m. It possesses a relatively large angular acceptance bandwidth, reducing the beam quality requirements for source lasers. 


  • Broad transparency range from 160nm to 2600nm

  • High optical homogeneity (dn10-6/cm) and being free of inclusion

  • Relatively large effective SHG coefficient (about three times that of KDP)

  • High damage threshold (18.9 GW/cm2 for a 1.3ns laser at 1053nm)

  • 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


  • Optical parametric amplifiers(OPA) and oscillators(OPO);

  • Frequency doubling(SHG) and tripling(THG)

  • Diode laser pumped Nd:YAG and Nd: YLF laser. Alexandrite, Ti:Sapphire, Dye Lasers, Ultrashort Pulse Lasers

Main Specifications  
Angle tolerance: Δθ< 0.5; Δφ< 0.5
Dimension tolerance: (W 0.1mm) x (H 0.1mm) x (L + 0.2mm/-0.1mm)
Flatness: λ/8 @ 633nm
Scratch/Dig code: 10/5 Scracth/dig per MIL-O-13830A
Parallelism: better than 10 arc seconds
Perpendicularity: 5 arc minutes
Wavefront distortion: less than λ/8 @ 633nm
Clear aperture: > 90% central area
Working temperature: 25C

AR/AR: 1064nm / 532nm R1064<0.1%  R532<0.2%
AR/AR: 532nm / 266nm  R532<0.2%   R266<0.5%
AR/AR: 1064nm / 355nm R1064<0.2%   R355<0.5%

To inquire or order a finished LBO crystals, please provide detailed specifications as listed in the above.  We require engineering drawing for specific orientation.  For special applications, please consult us for the designs if you are sure about the phase matching angle .

Physical and Chemial Properties  
Crystal structure Orthorhombic, Space group Pna21, Point group mm2
Melting point 834C
Lattice parameters a=8.4473, b=7.3788 , c=5.1395 , Z=2
Hardness ~6 Mohs 
Density 2.474 g/cm3
Thermal expansion coefficient ax=10.8x10-5/K, ay= -8.6x10-5/K, az=3.4x10-5/K
Absorption coefficient <0.1%/cm at 1064nm
Optical Properties
Transparency range 160 - 2600 nm
Refractive indices 
Wavelength nx ny ne
1064 nm 1.5656 1.5905 1.6055
532  nm 1.5785 1.6065 1.6212
355  nm 1.5973 1.6286 1.6444
Absorption coefficients a < 1%/cm @1.064mm and 0.532mm
Phase matching range 0.984 - 3.4 mm
Therm-optic coefficients dno/dT = - 9.3 x 10-6/C
dne/dT = -13.6 x 10-6/C
dne/dT = (-6.3+2.1λ) x 10-6/C
Sellmeier equations
N2x 2.454140+0.011249/(λ2-0.011350)-0.014591λ2 - 6.60 x 10-54 ( λ in m, T=200C) 
N 2.539070+0.012711/(λ2-0.012523)-0.018540λ2 + 2.00 x 10-44 ( λ in m, T=200C) 
N 2.586179+0.013099/(λ2-0.011893)-0.017968λ2 - 2.26 x 10-44 ( λ in m, T=200C) 
Conversion efficient
pulse  cw ( for Nd:YAG lasers)
SHG 70% 30%
THG 60% 
Laser Damage Threshold

18 GW/cm2 for a TEM00 mode, 1.3ns, 1Hz laser at 1064nm; 
1GW/cm2 for a cw, mode-locked laser at 1064nm. 

Nonlinear coefficients d31 =  1.05 0.09 pm/V
d32 = -0.98 0.09 pm/V
d33=  0.05 0.006 pm/V



 Toll Free(U.S.) 888.309.5061 Fax 650.618.2057

Copyright 2010 Red Optronics.  All Rights Reserved.