Nonlinear crystal

The nonlinear crystal is the crystal that reveals the nonlinear optical impact greater than twice for the laser electrical area. Nonlinear optical crystal is a kind of practical product, in which the frequency-doubling (or “frequency conversion”) crystal can be made use of to transform the laser wavelength, so as to prolong the tunable series of the laser, which has crucial application value in the field of laser modern technology.

There are hundreds of various types of nonlinear crystals, Common lithium niobate (LiNbO₃–LN), lithium tantalate (LiTaO₃–LT), potassium dihydrogen phosphate (KH₂PO₄–KDP), potassium deuterium phosphate (KD₂PO₄–DKDP), lithium iodate (LiIO₃–LI), potassium titanium phosphate (KTiOPO₄–KTP), barium metaborate (BaB₂O₄—BBO), lithium trisborate (LiB₃O₅–LBO), potassium niobate (KNbO₃–KN), cesium borate (CSB₃O₅–CBO), cesium lithium borate (LiCSB₆O₁₀–CLBO), potassium beryllium fluoroborate (KBe2BO₃F₂–KBBF), silver things (AgGaS₂–AGS), silver selenium gallium (AgGaSe₂–AGSe, arsenic-cadmium germanium (CDGEAS-CGA), cadmium selenide CdSe, Gallium selenide GaSe, phospho-germanium zinc (ZnGEP₂-ZGP) are commonly used in laser frequency increasing, amount regularity, distinction frequency, optical parametric boosting, electro-optic modulation, electro-optic deflection, etc.

Nonlinear crystal properties

For nonlinear optical crystals, along with having large reliable nonlinear coefficients, the following residential properties are additionally called for:

• As a whole, the crystal must have high transparency for the wavelength entailed;
• The inner absorption ought to be low, and the anti-damage threshold must be high;
• Stable physical and chemical buildings, moderate solidity, no deliquescence;
• Secure crystal quality, plus size, reasonable rate, and very easy covering.
• Below are some instances of typical nonlinear optical crystals

BBO nonlinear crystal

BaB₂O₄ crystals are identified as the most outstanding second-order nonlinear optical crystal worldwide. Among its amazing attributes is its large regularity inflection range. A lot more notably, by using its regularity down-conversion process, BBO crystal can be made right into a continuously tunable totally healed tuned laser with the wavelength from visible to near-infrared.

Barium borate (BBO) has big birefringence as well as low dispersion, high damage limit, large phase matching variety, excellent temperature level security, large nonlinear optical impact, as well as the regularity increasing coefficient is 6 times that of KDP crystal. It has an extreme variety of pervious to light, reduced absorption coefficient, a weaker piezoelectric buzzing effect, various other crystal electro-optic modulations, has higher extinction ratio, a bigger stage in a supporting function, high optical damage limit, a temperature level of the broadband matching, as well as outstanding optical homogeneity and to improve the laser output power stability, Specifically for the triple frequency Nd: YAG laser has a large range of applications.

LBO nonlinear crystal

Lithium trisborate, additionally known as LBO, is a superb high-power UV frequency-doubling crystal with a large transmittance band, high damage threshold, and also large acceptance Angle. Lithium trisborate (LiB₃O₅, described as LBO) crystal is usually made use of in middle and also high power 1064nm dual as well as three-way regularity lasers. It has a very high light damage resistance limit, very good light harmony, broad obtaining Angle, good mechanical properties, solid thermal shock resistance, microduplication, and also a large nonlinear coefficient. It is among the nonlinear crystals with excellent comprehensive properties.

The most significant benefit of LBO is that it can utilize temperature level tuning to achieve non-critical phase matching (NCPM). When the regularity-increasing process satisfies the non-critical phase matching relationship, the separation Angle between the essential regularity and also the 2nd harmonic of the regularity increasing is 0. At this time, the reliable length of the LBO crystal can theoretically reach infinity, which can make up for its little nonlinear coefficient. As a result of its huge damage limit, this suggests that high-power fundamental wave pumping can be achieved.

MgO: LiNbO₃ nonlinear crystal

Compared with LiNbO₃ crystal, MgO: LiNbO₃ crystal has special benefits in the application of NCPM frequency increasing, mixing, and optical parametric oscillation in ND-doped lasers.

The anti-damage threshold of drugged MgO: LiNbO₃ crystal is greater than twice more than that of pure LiNbO₃ crystal.