Lithium triborate
Encyclopedia
Lithium triborate LBO is a non-linear optics crystal
. It has a wide transparency range, moderately high nonlinear coupling, high damage threshold and desirable chemical and mechanical
properties. This crystal is often used for second harmonic generation
(SHG, also known as frequency doubling) of Nd:YAG laser
s (1064 nm → 532 nm). LBO can be both critically and non-critically phase-matched. In the latter case the crystal has to be heated or cooled depending on the wavelength
.
Lithium triborate is an excellent nonlinear optical crystal discovered and
developed by Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences
. It has been patented.
Crystal
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...
. It has a wide transparency range, moderately high nonlinear coupling, high damage threshold and desirable chemical and mechanical
Mechanics
Mechanics is the branch of physics concerned with the behavior of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment....
properties. This crystal is often used for second harmonic generation
Second harmonic generation
An optical frequency multiplier is a nonlinear optical device, in which photons interacting with a nonlinear material are effectively "combined" to form new photons with greater energy, and thus higher frequency...
(SHG, also known as frequency doubling) of Nd:YAG laser
Nd:YAG laser
Nd:YAG is a crystal that is used as a lasing medium for solid-state lasers. The dopant, triply ionized neodymium, typically replaces yttrium in the crystal structure of the yttrium aluminium garnet , since they are of similar size...
s (1064 nm → 532 nm). LBO can be both critically and non-critically phase-matched. In the latter case the crystal has to be heated or cooled depending on the wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
.
Lithium triborate is an excellent nonlinear optical crystal discovered and
developed by Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences
Chinese Academy of Sciences
The Chinese Academy of Sciences , formerly known as Academia Sinica, is the national academy for the natural sciences of the People's Republic of China. It is an institution of the State Council of China. It is headquartered in Beijing, with institutes all over the People's Republic of China...
. It has been patented.
Chemical properties
- Point groupPoint groupIn geometry, a point group is a group of geometric symmetries that keep at least one point fixed. Point groups can exist in a Euclidean space with any dimension, and every point group in dimension d is a subgroup of the orthogonal group O...
: mm2 - Lattice parameters: a=8.4473 Å, b=7.3788 Å, c=5.1395 Å
- Mohs hardness: 6
- Transmission range: 0.16 – 2.6 μm
- Damage threshold: 25 J/cm2 (1064 nm, 10 ns pulses)
- Thermal expansion coefficients: x: 10.8×10−5/K, y: −8.8×10−5/K, z: 3.4×10−5/K
- Specific heat: 1060 J/kg·K
- Melting point: 834 °C
Applications of Lithium Triborate (LBO) Crystal
Lithium Triborate (LBO) crystals are applicable in various nonlinear optical applications:- Frequency doubling (SHG) and frequency tripling of high peak power pulsed Nd doped, Ti:Sapphire lasersTi-sapphire laserTi:sapphire lasers are tunable lasers which emit red and near-infrared light in the range from 650 to 1100 nanometers. These lasers are mainly used in scientific research because of their tunability and their ability to generate ultrashort pulses...
and Dye lasersDye laserA dye laser is a laser which uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths. The wide bandwidth makes them particularly suitable for tunable lasers and... - NCPM (non-critical phase matching for frequecy conversion of CW and quasi CW radiation
- OPO (Optical Parametric OscillatorsOptical parametric oscillatorAn optical parametric oscillator is a parametric oscillator which oscillates at optical frequencies. It converts an input laser wave into two output waves of lower frequency by means of second order nonlinear optical interaction. The sum of the output waves frequencies is equal to the input wave...
} of both Type 1 and Type 2 phase-matching