Recent developments of NLO crystals in the visible and ultraviolet regions

With the development of all-solid state laser systems for the green, blue and even UV coherent beams, there are extensive needs for NLO crystals which can perform harmonic generation in these regions. It may be for this promotion in recent years that great efforts have been made to successfully improve optical properties and quality of the existed NLO crystals (KTP, BBO and LBO), along with development of new generation of NLO crystals, for the UV region in particular. It is of interest to note that All these research works till now are almost concentrated in the Pacific rim area.