Multipurpose noncentrosymmetric laser crystals

A review is given of the properties of noncentrosymmetric laser crystals with the structures of the huntite, melilite, fresnoite, potassium neodymium tetrametaphosphate, and thorium phosphide type, as well as ferroelastics of the neodymium pentaphosphate, fergusonite, and elpasolite type. The probability of manifestation of the required properties is estimated for several materials (including pyroelectric ceramics) when only information on the structure is available.