The nonlinear optical crystal is the crystal which shows the nonlinear optical result more than twice for the laser electric area. Nonlinear optical crystal is a type 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 extend the tunable variety of the laser, which has important application value in the field of laser modern technology.
Properties of nonlinear crystals
For nonlinear optical crystals, along with having big reliable nonlinear coefficients, the adhering to buildings are likewise called for:
- Generally, the crystal should have high transparency for the wavelength involved;
- the inner absorption must be low, the anti-damage threshold should be high;
- Steady physical as well as chemical properties, modest solidity, no deliquescence;
- Steady crystal high quality, large size, reasonable cost, simple finish.
Below are some examples of typical nonlinear optical crystals
BBO nonlinear crystal is acknowledged as one of the most exceptional second-order nonlinear optical crystal on the planet. One of its exceptional qualities is its broad regularity modulation array. A lot more significantly, by utilizing its regularity down-conversion procedure, BBO crystal can be made into a constantly tunable fully healed tuned laser with wavelength from noticeable to near-infrared.
Barium borate (BBO) has big birefringence as well as reduced dispersion, high damage limit, vast phase matching variety, excellent temperature security, big nonlinear optical impact, as well as the regularity increasing coefficient is six times that of KDP crystal. It has a very large range of pervious to light, low absorption coefficient, the weaker the piezoelectric buzzing effect, relative to various other crystal electro-optic inflection, has higher termination proportion, the larger stage in a supporting duty, high optical damage limit, the temperature level of the broadband matching, as well as exceptional optical homogeneity and also to enhance the laser output power security, Particularly for the three-way regularity Nd: YAG laser has a variety of applications.
Lithium trisborate, also called LBO, is a superb high-power UV frequency-doubling crystal with broad passage band, high damage threshold and large acceptance Angle. Lithium trisborate (LiB3O5, referred to as LBO) crystal is typically utilized in middle and also high power 1064nm double as well as three-way regularity lasers. It has extremely high light damages resistance threshold, excellent light uniformity, broad getting Angle, excellent mechanical properties, solid thermal shock resistance, microdelixation, as well as huge nonlinear coefficient. It is one of the nonlinear crystals with superb comprehensive residential or commercial properties.
The most significant benefit of LBO is that it can utilize temperature adjusting to achieve non-critical stage matching (NCPM). When the frequency increasing process pleases the non-critical phase matching relation, the separation Angle in between the basic frequency and the 2nd harmonic of the regularity increasing is 0. At this time, the efficient size of the LBO crystal can theoretically get to infinity, which can compensate for its tiny nonlinear coefficient. Because of its big damages threshold, this implies that high-power essential wave pumping can be accomplished.
Compared with LiNbO3 crystal, MgO: LiNbO3 crystal has its distinct advantages in the application of NCPM regularity increasing, blending and also optical parametric oscillation in ND-doped lasers.
The anti-damage threshold of doped MgO: LiNbO3 crystal is more than two times higher than that of pure LiNbO3 crystal.