Barium beta-borate

Only certain types of crystalline materials can exhibit second harmonic generation (61). Because of symmetry considerations, the coefficient must be identically equal to zero in any material having a center of symmetry. Thus the only candidates for second harmonic generation are materials that lack a center of symmetry. Some common materials which are used in nonlinear optics include barium sodium niobate [12323-03-4] Ba2NaNb O lithium niobate [12031 -63-9] LiNbO potassium titanyl phosphate [12690-20-9], KTiOPO beta-barium borate [13701 -59-2], p-BaB204 and lithium triborate... 

Limitations of the SH output power generated by pulsed lasers are mainly set by the damage threshold of available nonlinear crystals. Very promising new crystals are the negative uniaxial BBO (beta-barium borate) [5.225-5.228] and lithium borate LiBO, which have high damage thresholds and which allow SHG from 205 nm to above 3000 nm. 

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