Lithium Tetra Borate

Material
LBO

 

Lithium Tetra Borate (LBO or LiB3O5) is a known non-linear crystal with a high transmission range from the VUV to IR. Its high damage threshold and its chemical and mechanical properties makes it suitable for non-linear optical applications. That is why it is often used for frequency doubling of Nd:YAG lasers. The high energy band gap makes it resistant against UV radiation.

 

The LBO crystals can be used for SHG (second harmonic generation) and THG (third harmonic generation) of pulsed Nd:YAG lasers, Ti:Sapphire lasers and dye lasers where also high pulse energies are allowed. Another application is the frequency conversion of cw and quasi-cw radiation by non-critical phase matching (NCPM). An OPO (optical parametric oscillator) can be set up with both by type I as well as by type II phase-matching. The crystals work also well for optical parametric chirped-pulse amplification (OPCPA).

Properties
Optical properties
Transmission range
160 ‐ 2600
Refractive index @532 nm
nx = 1,5785

ny = 1,1,6065

nz = 1,6212

Refractive index @ 1064 nm
nx = 1,5656

ny = 1,5905

nz = 1,6055

NLO coefficients in pm/V, @1064 nm
d31 = 0,85

d32 = -0,67

d33 = 0,04

d34 = 6,1

Absorption loss in %/cm
<0,3 @ 532 nm

<0,01 @ 1064 nm

Temperature acceptance in °C·cm
4,7 (Typ I, 1064 nm SHG)

7,5 (Typ II, 1064 nm SHG)

Spectral acceptance in nm·cm
1,0 (Typ I, 1064 nm)

1,3 (Typ II, 1064 nm)

Angular acceptance in mrad·cm
6,54 (Typ I, 1064 nm φ)

15,27(Typ II. 1064 nm θ)

Walk-off-angle
0,6° (Typ I, 1064 nm)

0,12° (Typ II, 1064 nm)

Physical properties
Chemical formula
LiB3O5
Density in g/cm3
2,47
Melting point in °C
834
Lattice constants in Å
a = 8,4473

b = 7,3788

c = 5,1395

Crystal structure
orthorhombic
Thermal conductivity in W/(m·K)
3,5
Thermal expansion in 1/K
αx = 10,8·10-5

αy = -8,8·10-5 ·10-6

αz = 3,4·10-5 ·10-6

Mohs hardness
6
Spectral properties