Lithium Triborate (LBO)

KOMLAS offers high quality KTP-, BBO- and LBO- crystals. The right material should be chosen taking into consideration the criteria transmission, damage threshold, efficiency of the nonlinear effect, phase matching range and laser beam quality.

The damage threshold is a function of the wavelength of fundamental and harmonic radiation, pulse duration, beam profile and other parameters. For guidance typical values are given in the table ( = 1064 nm, pulse duration 1.3 ns).

max. energy density [J/cm²]:
KTP 4.6
BBO 9.9
LBO 18.9
LBO (LiB3O5) is a nonlinear crystal with excellent physical and optical properties. Its high optical homogenity, nonhygroscopicity, low walk-off and very high damage threshold make this crystal perfectly suitable for harmonic generation as well as sum frequency generation and OPG/OPA applications. LBO is the first choice for making doubler or tripler for lasers such as Nd:YAG where high power density, high stability, and long time operation are required.

LBO crystals with large aperture and length for harmonic generation and OPO of high average/peak power Q-switched Nd:YAG lasers are available from KOMLAS as well as thin crystals for ultrafast lasers with femtosecond (fs) pulse width. Noncritical phase matching in wide range made possible by temperature tuning allows the usesage of long crystals without almost any walk-off influence on nonlinear interaction efficiency.

Crystal structure
Point group
 Space group
Lattice constants [Å]
Density [g/cm-3]
Melting point [°C]
Mohs hardness
Absorption [cm-1] at 1064 nm
532 nm
Thermal expansion coefficients [10–5/K]
Refractive indices at  1064 nm
  532 nm
 266 nm
Thermo-optic coefficients [10-6/K]
orthorhombic
mm²
Pna21
a= 8.447 b= 7.380 c= 5.120
2.47 
834
6
< 0.002 
< 0.003
x = 10.8 y = 8.8 z = 3.4 
nx = 1.5656 ny = 1.5905 nz = 1.6055
nx = 1.5785 ny = 1.6065 nz = 1.6212
nx = 1.5973 ny = 1.6286 nz = 1.6444
dnx/dT = -9.3 dny/dT = -13.6 dnz/dT = -6.3 + 2.1
Wavelength dispersion of refractive index (Sellmeier equitions)
nx²= 2.45414 +0.01125/(λ² -0.01135) - 0.01460 λ² - 6.6 x 10-5 λ4 (λ in µm, T=20 °C)
ny²= 2.53907 +0.01272/(λ² -0.01252) - 0.01854 λ² + 2.0 x 10-4 λ4 (λ in µm, T=20 °C)
nz²= 2.58618 +0.01310/(λ² -0.01189) - 0.01797 λ² - 2.3 x 10-4 λ4 (λ in µm, T=20 °C)
Walk-off for Type 1 SHG @ 1064 nm [mrad]

Effective nonlinearity d31[m/V]
d32[m/V]
d33[m/V]
2

(1.07 ±0.09) x 10-12 
(1.05 ±0.10) x 10-12 
(0.05 ±0.01) x 10-12 
KOMLAS offers:

  • Crystal length up to 30 mm and aperture up to 20 mm x 20 mm
  • Crystal length down 0.1 mm for ultrafast lasers
  • Dualband and tripleband AR coatings
  • P-coatings
  • Determination of necessary angular orientation