Lithium triborate (LiB₃O₅) or LBO is a

non-linear optics Nonlinear optics (NLO) is the branch of optics that describes the behaviour of light in ''nonlinear media'', that is, media in which the polarization density P responds non-linearly to the electric field E of the light. The non-linearity is typica ...

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

. It has a wide transparency range, moderately high nonlinear coupling, high damage threshold and desirable

chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wi ...

and

mechanical Mechanical may refer to: Machine * Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement * Mechanical calculator, a device used to perform the basic operations of ...

properties. This crystal is often used for

second harmonic generation Second-harmonic generation (SHG, also called frequency doubling) is a nonlinear optical process in which two photons with the same frequency interact with a nonlinear material, are "combined", and generate a new photon with twice the energy of ...

(SHG, also known as ''frequency doubling''), for example of Nd:YAG lasers (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 In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...

. Lithium triborate was discovered and developed by Chen Chuangtian and others of the Fujian Institute of Research on the Structure of Matter,

Chinese Academy of Sciences The Chinese Academy of Sciences (CAS); ), known by Academia Sinica in English until the 1980s, is the national academy of the People's Republic of China for natural sciences. It has historical origins in the Academia Sinica during the Republ ...

. It has been patented.

Chemical properties

Point group In geometry, a point group is a mathematical group of symmetry operations (isometries in a Euclidean space) that have a fixed point in common. The coordinate origin of the Euclidean space is conventionally taken to be a fixed point, and every p ...

: mm2 *

Lattice parameter A lattice constant or lattice parameter is one of the physical dimensions and angles that determine the geometry of the unit cells in a crystal lattice, and is proportional to the distance between atoms in the crystal. A simple cubic crystal has o ...

s: ''a''=8.4473 Å, ''b''=7.3788 Å, ''c''=5.1395 Å *

Mohs hardness The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by th ...

: 6 *Transmission range: 0.16 – 2.6 μm * Damage threshold: 25 J/cm² (1064 nm, 10 ns pulses) *

Thermal expansion coefficient Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic ...

s: ''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:LBO crystal applications at www.eksmaoptics.com
/ref> * Frequency doubling (SHG) and frequency tripling of high peak power pulsed Nd doped, Ti:Sapphire lasers and

Dye laser A dye laser is a laser that 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, often spanning 50 to 100 na ...

s *NCPM (non-critical phase matching for frequency conversion of CW and quasi CW radiation *OPO (

Optical parametric oscillator An optical parametric oscillator (OPO) is a parametric oscillator that oscillates at optical frequencies. It converts an input laser wave (called "pump") with frequency \omega_p into two output waves of lower frequency (\omega_s, \omega_i) by mean ...

) of both Type 1 and Type 2 phase-matching

References

External links

LBO Crystal (Lithium Triborate) at www.redoptronics.com
{{Lithium compounds Borates Nonlinear optical materials Crystals Lithium compounds