The nonlinear crystal is the crystal that reveals the nonlinear optical effect greater than twice for the laser electric area. Nonlinear optical crystal is a type of useful material, in which the frequency-doubling (or “regularity conversion”) crystal can be utilized to transform the laser wavelength, so regarding prolong the tunable range of the laser, which has an important application worth in the field of laser technology.
There are numerous various kinds 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 fluorborate (KBe2BO3F2– KBBF), silver thiogas (AgGaS2– AGS), silver selenium gallium (AgGaSe2– AGSe, arsenic-cadmium germanium (CDGEAS-CGA), cadmium selenide CdSe, Gallium selenide GaSe, phospho-germanium zinc (ZnGEP2-ZGP) are widely utilized in laser frequency doubling, sum regularity, difference frequency, optical parametric amplification, electro-optic inflection, electro-optic deflection, etc.
Nonlinear crystal residential properties
For nonlinear optical crystals, along with having large efficient nonlinear coefficients, adhering to homes is also needed:
1. In general, the crystal needs to have high openness for the wavelength involved;
2, the internal absorption must be low, and the anti-damage threshold ought to be high;
3. Stable physical and chemical residential or commercial properties, moderate solidity, no deliquescence;
4. Secure crystal top quality, plus size, realistic price, and simple finish.
Right here are some instances of typical nonlinear optical crystals
BBO
BBO crystal is identified as one of the most superb second-order nonlinear optical crystals in the world. One of its amazing attributes is its large frequency modulation range. A lot more notably, by using its regularity down-conversion process, BBO crystal can be made into a constantly tunable fully treated tuned laser with the wavelength from visible to near-infrared.
Barium borate (BBO) has huge birefringence and also low diffusion, high damages threshold, broad stage matching range, good temperature level stability, huge nonlinear optical impact, and also the regularity increasing coefficient is six times that of KDP crystal. It has a really large range of pervious to light, low absorption coefficient, weak piezoelectric ringing effect, about various other crystal electro-optic inflection, has higher extinction proportion, a larger stage in a supporting role, high optical damage threshold, a temperature of the broadband matching, and also outstanding optical homogeneity and to boost the laser result power security, Specifically for the triple regularity Nd: YAG laser has a wide variety of applications.
LBO
Lithium trisborate, likewise called LBO, is a superb high-power UV frequency-doubling crystal with a large transmittance band, high damage threshold as well a huge acceptance Angle. Lithium trisborate (LiB3O5, referred to as LBO) crystal is often utilized in the center and high power 1064nm dual and triple frequency lasers. It has an extremely high light damage resistance threshold, excellent light uniformity, wide receiving Angle, good mechanical residential or commercial properties, strong thermal shock resistance, microdelixation, and a large nonlinear coefficient. It is just one of the nonlinear crystals with outstanding comprehensive properties.
The greatest advantage of LBO is that it can utilize temperature level tuning to attain non-critical stage matching (NCPM). When the regularity doubling procedure pleases the non-critical phase matching relationship, the departure Angle between the essential regularity and the 2nd harmonic of the regularity doubling is 0. The efficient length of the LBO crystal can, in theory, reach infinity, which can make up for its little nonlinear coefficient. Due to its large damage limit, this indicates that high-power fundamental wave pumping can be attained.
MgO: LiNbO3.
Compared to LiNbO3 crystal, MgO: LiNbO3 crystal has its unique advantages in the application of NCPM frequency doubling, blending as well as an optical parametric oscillation in ND-doped lasers.
The anti-damage limit of drugged MgO: LiNbO3 crystal is greater than twice more than that of pure LiNbO3 crystal.
